UNITED STATES
	SECURITIES AND EXCHANGE COMMISSION
	Washington, D.C. 20549

	FORM 10-Q


[X]	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
EXCHANGE ACT OF 1934
For the quarterly period ended March 31, 2007 or

[ ]	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934
For the transition period from                to

Commission File Number 0-18314

	MORGAN STANLEY PRINCIPAL PLUS FUND L.P.

	(Exact name of registrant as specified in its charter)

		Delaware						     13-3541588
(State or other jurisdiction of		   		  (I.R.S. Employer
incorporation or organization)			       Identification No.)


Demeter Management Corporation
330 Madison Avenue, 8th Floor
New York, NY							      	10017
(Address of principal executive offices)	  	         (Zip Code)

Registrant?s telephone number, including area code       (212) 905-2700



(Former name, former address, and former fiscal year, if changed since
last report)

Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange
Act of 1934 during the preceding 12 months (or for such shorter period
that the registrant was required to file such reports), and (2) has been
subject to such filing requirements for the past 90 days.

Yes    X       	No__________

Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, or a non-accelerated filer.  See definition
of ?accelerated filer and large accelerated filer? in Rule 12b-2 of the
Exchange Act.  (Check one):

Large accelerated filer___Accelerated filer____Non-accelerated filer X

Indicate by check mark whether the registrant is a shell company (as
defined in Rule 12b-2 of the Exchange Act).  Yes___  No X


	<page> <table> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.

	INDEX TO QUARTERLY REPORT ON FORM 10-Q

	March 31, 2007

<caption>


PART I. FINANCIAL INFORMATION

				<c>
Item 1. Financial Statements

	Consolidated Statements of Financial Condition as of
	March 31, 2007 (Unaudited) and December 31, 2006..............2

	Consolidated Statements of Operations for the Quarters
	Ended March 31, 2007 and 2006 (Unaudited).....................3

	Consolidated Statements of Changes in Partners? Capital for
the Quarters Ended March 31, 2007 and 2006 (Unaudited)........4

	Consolidated Statements of Cash Flows for the Quarters
	Ended March 31, 2007 and 2006 (Unaudited).....................5

	Notes to Consolidated Financial Statements (Unaudited).....6-13

Item 2.	Management?s Discussion and Analysis of
			Financial Condition and Results of Operations........14-23

Item 3.	Quantitative and Qualitative Disclosures about
			Market Risk..........................................24-37

Item 4.	Controls and Procedures.................................37

Item 4T.	Controls and Procedures.................................38


PART II. OTHER INFORMATION

Item 1A.Risk Factors............................................39

Item 6.	Exhibits................................................39


</table>


<page> <table> PART I.  FINANCIAL INFORMATION

Item 1.  Financial Statements

	MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
	CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION
<caption>
	                       March 31,	     December 31,
                              2007      	    2006
	                      $	    $
	                        (Unaudited)
ASSETS

	<c>	<c>
Equity in futures interests trading accounts:
	Unrestricted cash	12,545,493	13,545,110
    Restricted cash						               540,115	       681,672

	     Total cash	   13,085,608	   14,226,782

	Net unrealized gain on open contracts (MSIL)	80,944	     11,335
	Net unrealized gain on open contracts (MS&Co.)	            25,902	         10,199

	     Total net unrealized gain on open contracts	        106,846	         21,534

	     Total Trading Equity	13,192,454	  14,248,316

Interest receivable (Morgan Stanley DW)	          53,990	          56,037

	     Total Assets	   13,246,444	   14,304,353

LIABILITIES AND PARTNERS? CAPITAL

Liabilities

Redemptions payable	156,585	137,293
Accrued administrative expenses	96,077	99,434
Accrued brokerage fees (Morgan Stanley DW)	43,835	47,350
Accrued management fees  	        10,958	         11,838

     Total Liabilities                                  307,455	      295,915

Minority Interest	           (271)	          3,253

Partners? Capital

Limited Partners (6,827.697 and
   7,225.105 Units, respectively)	12,737,719	13,798,864
General Partner (108.030 Units)	      201,541	        206,321

	     Total Partners? Capital	  12,939,260  	   14,005,185

	     Total Liabilities and Partners? Capital	   13,246,444	   14,304,353


NET ASSET VALUE PER UNIT 	       1,865.60	       1,909.85
<fn>

	The accompanying notes are an integral part
	of these consolidated financial statements.
</table>


	<page> <table> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
	CONSOLIDATED STATEMENTS OF OPERATIONS
(Unaudited)

	<caption>

  	   	    For the Quarters Ended March 31,


                                                                         	          2007    	      2006
                                                                                                     $		          $

		<c>			<c>
INVESTMENT INCOME
	Interest income (Morgan Stanley DW)	     155,921			    159,682

EXPENSES
	Brokerage fees (Morgan Stanley DW)	135,945	167,208
	Management fees	     	33,986	 41,802
	Administrative expenses		 29,000	   25,000
	Transaction fees and costs		      12,560	        12,516

		   Total Expenses		     211,491	      246,526

NET INVESTMENT LOSS	      (55,570)	      (86,844)

TRADING RESULTS
Trading profit (loss):
	Realized			(349,679)	(217,664)
	Net change in unrealized		      85,312	     361,611

    Total Trading Results		   (264,367)	     143,947

NET INCOME (LOSS) BEFORE MINORITY INTEREST         (319,937)	   57,103

Less:  Minority Interest		        (3,524)	            301

NET INCOME (LOSS)		    (316,413)	       56,802

NET INCOME (LOSS) ALLOCATION

	Limited Partners                                                  		(311,633)	56,071
	General Partner       	                                                                    (4,780)	731

NET INCOME (LOSS) PER UNIT

	Limited Partners                                                             	(44.25)	  6.77
  	General Partner                                                  		       (44.25)	  6.77


<fn>



The accompanying notes are an integral part
of these consolidated financial statements.
</table>


<page> <table> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
	CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS? CAPITAL
	For the Quarters Ended March 31, 2007 and 2006
	(Unaudited)


<caption>


	  Units of
	   Partnership	Limited	General
	   Interest   	Partners	Partner	   Total
		$	$	   $

	<c>	<c>	<c>	<c>
Partners? Capital,
	December 31, 2005	   8,927.367	16,716,099	          204,759	              16,920,858

Net Income                   	?		56,071	731	56,802

Redemptions	      (418.588)	 (792,624)                 ?      	  (792,624)

Partners? Capital,
	March 31, 2006  	          8,508.779	  15,979,546	  205,490	 16,185,036




Partners? Capital,
	December 31, 2006	   7,333.135	13,798,864	          206,321	              14,005,185

Net Loss                   	?		(311,633)	(4,780)	(316,413)

Redemptions	      (397.408)	    (749,512)                 ?      	  (749,512)

Partners? Capital,
	March 31, 2007  	          6,935.727	  12,737,719	  201,541	 12,939,260





<fn>











The accompanying notes are an integral part
	of these consolidated financial statements.
</table>


<page> <table> 	MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
	CONSOLIDATED STATEMENTS OF CASH FLOWS
(Unaudited)


<caption>


	          For the Quarters Ended March 31,

	      2007     	      2006
	      $	      $


CASH FLOWS FROM OPERATING ACTIVITIES

			<c>	<c>
Net income (loss)	(316,413)	56,802
Noncash item included in net income (loss):
	Net change in unrealized	(85,312)	(361,611)

(Increase) decrease in operating assets:
	Restricted cash	141,557	(239,941)
	Interest receivable (Morgan Stanley Dw)	2,047	(4,177)

Increase (decrease) in operating liabilities:
	Accrued administrative expenses	(3,357)	3,070
	Accrued brokerage fees (Morgan Stanley DW)	(3,515)	(2,640)
	Accrued management fees	            (880)	              (659)

Net cash used for operating activities	    (265,873)	       (549,156)


CASH FLOWS FROM FINANCING ACTIVITIES

Cash paid for redemptions of Units	(730,220)	(845,769)
Increase (decrease) in minority interest	          (3,524)	               302

Net cash used for financing activities	     (733,744)	      (845,467)

Net decrease in unrestricted cash	(999,617)	(1,394,623)

Unrestricted cash at beginning of period	 13,545,110	   16,730,219

Unrestricted cash at end of period	  12,545,493	  15,335,596





<fn>





	The accompanying notes are an integral part
	of these consolidated financial statements.
</table>


<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

March 31, 2007

(Unaudited)

The unaudited consolidated financial statements contained herein
include, in the opinion of management, all adjustments necessary
for a fair presentation of the results of operations and financial
condition of Morgan Stanley Principal Plus Fund L.P. (the
?Partnership?).  The consolidated financial statements and
condensed notes herein should be read in conjunction with the
Partnership?s December 31, 2006, Annual Report on Form 10-K.

1.  Organization
Morgan Stanley Principal Plus Fund L.P. is a Delaware limited
partnership organized in 1989 to engage primarily in the
speculative trading of futures contracts, options on futures
contracts, and forward contracts on physical commodities and other
commodity interests (collectively, ?Futures Interests?).

The Partnership?s general partner is Demeter Management
Corporation (?Demeter?).  Effective April 1, 2007, Morgan Stanley
DW Inc. (?Morgan Stanley DW?), which previously acted as the non-
clearing broker, was merged into Morgan Stanley & Co. Incorporated
(?MS&Co.?), which has assumed all of the responsibilities of
Morgan Stanley DW.  Upon completion of the merger, MS&Co. has

<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

become the Partnership?s principal commodity broker-dealer and
also acts as the counterparty on all trading of foreign currency
forward contracts.  In addition, Morgan Stanley & Co.
International Limited (?MSIL?) serves as the commodity broker for
trades on the London Metal Exchange.  Effective April 13, 2007,
Morgan Stanley & Co. International Limited changed its name to
Morgan Stanley & Co. International plc.  The commodity brokers
prior to April 1, 2007, were Morgan Stanley DW, MS&Co., and MSIL.
 Demeter, MS&Co., and MSIL are wholly-owned subsidiaries of Morgan
Stanley.  The trading advisor to the Partnership is SSARIS
Advisors, LLC (the ?Trading Advisor?).  Morgan Stanley Principal
Plus Fund Management L.P. (the ?Trading Company?) was established
solely to trade in Futures Interests on behalf of the Partnership.

2.  Related Party Transactions
The Partnership?s and Trading Company?s cash is on deposit with
Morgan Stanley DW (through March 31, 2007), MS&Co., and MSIL in
futures, forward, and options trading accounts to meet margin
requirements as needed.  Effective April 1, 2007, MS&Co. pays
monthly interest income on 100% and 90% of the Partnership?s and
the Trading Company?s, respectively, average daily Net Assets for
the month at a rate equal to the monthly average yield on 4-week
U.S. Treasury bills discount rate during such month.  The Trading


<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

Company pays brokerage fees to MS&Co. (Morgan Stanley DW, prior to
April 1, 2007).  Prior to April 1, 2007, Morgan Stanley DW paid
monthly interest income on 100% and 90% of the Partnership?s and
the Trading Company?s, respectively, average daily Net Assets as
defined in the Limited Partnership Agreement for the month at the
prevailing rate on U.S. Treasury bills.

3.  Financial Instruments
The Partnership trades Futures Interests.  Futures and forwards
represent contracts for delayed delivery of an instrument at a
specified date and price.  Risk arises from changes in the value
of these contracts and the potential inability of counterparties
to perform under the terms of the contracts.  There are numerous
factors which may significantly influence the market value of
these contracts, including interest rate volatility.


The market value of exchange-traded contracts is based on the
settlement price quoted by the exchange on the day with respect
to which market value is being determined.  If an exchange-traded
contract could not have been liquidated on such day due to the
operation of daily limits or other rules of the exchange, the
settlement price shall be the settlement price on the first



<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)



subsequent day on which the contract could be liquidated.  The
market value of off-exchange-traded contracts is based on the fair
market value quoted by the counterparty.


The Partnership?s contracts are accounted for on a trade-date
basis and marked to market on a daily basis.  The Partnership
accounts for its derivative investments in accordance with the
provisions of Statement of Financial Accounting Standards No.
133, ?Accounting for Derivative Instruments and Hedging
Activities? (?SFAS No. 133?).  SFAS No. 133 defines a derivative
as a financial instrument or other contract that has all three of
the following characteristics:

1)	One or more underlying notional amounts or payment
provisions;
2)	Requires no initial net investment or a smaller initial net
investment than would be required relative to changes in
market factors;
3)	Terms require or permit net settlement.

Generally, derivatives include futures, forward, swap or options
contracts, and other financial instruments with similar
characteristics such as caps, floors, and collars.


<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

The net unrealized gains on open contracts, reported as a
component of ?Equity in futures interests trading accounts? on the
Consolidated Statements of Financial Condition, and their longest
contract maturities were as follows:

	Net Unrealized Gains
	on Open Contracts	Longest Maturities
		Off-			Off-
	Exchange-	Exchange-		Exchange-	Exchange-
Date	 Traded 	 Traded 	Total	 Traded 	 Traded
	  $	   $	  $
Mar. 31, 2007	106,846	-  	106,846    	Sep. 2007       -
Dec. 31, 2006	21,534	-  	21,534    	Jun. 2007       -

The Partnership has credit risk associated with counterparty non-
performance.  As of the date of the financial statements, the
credit risk associated with the instruments in which the
Partnership trades is limited to the amounts reflected in the
Partnership?s Consolidated Statements of Financial Condition.

The Partnership also has credit risk because Morgan Stanley DW
(through March 31, 2007), MS&Co., and MSIL act as the futures
commission merchants or the counterparties, with respect to most
of the Partnership?s assets. Exchange-traded futures, exchange-
traded forward, and exchange-traded futures-styled options
contracts are marked to market on a daily basis, with variations
in value settled on a daily basis.  Morgan Stanley DW (through
March 31, 2007), MS&Co., and MSIL, each as a futures

<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

commission merchant for the Partnership?s exchange-traded futures,
exchange-traded forward, and exchange-traded futures-styled
options contracts, are required, pursuant to regulations of the
Commodity Futures Trading Commission (?CFTC?), to segregate from
their own assets, and for the sole benefit of their commodity
customers, all funds held by them with respect to exchange-traded
futures, exchange-traded forward, and exchange-traded futures-
styled options contracts, including an amount equal to the net
unrealized gains (losses) on all open exchange-traded futures,
exchange-traded forward, and exchange-traded futures-styled
options contracts, which  funds, in the aggregate, totaled
$13,192,454 and $14,248,316 at March 31, 2007, and December 31,
2006, respectively.  With respect to the Partnership?s off-
exchange-traded forward currency contracts, there are no daily
settlements of variation in value, nor is there any requirement
that an amount equal to the net unrealized gains (losses) on such
contracts be segregated.  However, the Partnership is required to
meet margin requirements equal to the net unrealized loss on open
forward currency contracts in the Partnership accounts with the
counterparty, which is accomplished by daily maintenance of the
cash balance in a custody account held at Morgan Stanley DW for
the benefit of MS&Co.  With respect to those off-exchange-traded
forward currency contracts, the Partnership is at risk to the

<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)


ability of MS&Co., the sole counterparty on all such contracts, to
perform. The Partnership has a netting agreement with MS&Co.
This agreement, which seeks to reduce both the Partnership?s and
MS&Co.?s exposure to off-exchange-traded forward currency
contracts, should materially decrease the Partnership?s credit
risk in the event of MS&Co.?s bankruptcy or insolvency.

4.  New Accounting Developments
In July 2006, the Financial Accounting Standards Board (?FASB?)
issued interpretation No. 48, ?Accounting for Uncertainty in
Income Taxes ? an interpretation of FASB Statement 109? (?FIN
48?).  FIN 48 clarifies the accounting for income taxes by
prescribing the minimum recognition threshold a tax position must
meet before being recognized in the financial statements.  FIN 48
is effective for the Partnership as of January 1, 2007.  Based on
its analysis, management believes that the adoption of FIN 48
will not impact the Partnership?s Financial Statements.




In September 2006, the FASB issued SFAS No. 157, ?Fair Value
Measurements? (?SFAS No. 157?).  SFAS No. 157 defines fair value,
establishes a framework for measuring fair value, and expands
disclosures about fair value measurements.  SFAS NO. 157 is
effective for the Partnership as of January 1, 2008.  The impact

<page> MORGAN STANLEY PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONCLUDED)

to the Partnership?s Financial Statements, if any, is currently
being assessed.



<page> Item 2.	MANAGEMENT?S DISCUSSION AND ANALYSIS OF FINANCIAL
	CONDITION AND RESULTS OF OPERATIONS


Liquidity.  The Partnership deposits its assets with Morgan
Stanley DW (through March 31, 2007), MS&Co., and MSIL as commodity
brokers in separate futures, forward, and options trading accounts
established for the Trading Advisor.  Such assets are used as
margin to engage in trading and may be used as margin solely for
the Partnership?s trading. The assets are held in either non-
interest bearing bank accounts or in securities and instruments
permitted by the CFTC for investment of customer segregated or
secured funds.  Since the Partnership?s sole purpose is to trade
in futures, forwards, and options, it is expected that the
Partnership will continue to own such liquid assets for margin
purposes.

The Partnership?s investment in futures, forwards, and options
may, from time to time, be illiquid.  Most U.S. futures exchanges
limit fluctuations in prices during a single day by regulations
referred to as ?daily price fluctuations limits? or ?daily
limits?.  Trades may not be executed at prices beyond the daily
limit.  If the price for a particular futures or options contract
has increased or decreased by an amount equal to the daily limit,
positions in that futures or options contract can neither be taken
nor liquidated unless traders are willing to effect trades at or
within the limit.  Futures prices have occasionally moved the
daily limit for several consecutive days with little or no <page>
trading. These market conditions could prevent the Partnership
from promptly liquidating its futures or options contracts and
result in restrictions on redemptions.

There is no limitation on daily price moves in trading forward
contracts on foreign currencies.  The markets for some world
currencies have low trading volume and are illiquid, which may
prevent the Partnership from trading in potentially profitable
markets or prevent the Partnership from promptly liquidating
unfavorable positions in such markets, subjecting it to
substantial losses.  Either of these market conditions could
result in restrictions on redemptions. For the periods covered by
this report, illiquidity has not materially affected the
Partnership?s assets.

There are no known material trends, demands, commitments, events,
or uncertainties at the present time that are reasonably likely to
result in the Partnership?s liquidity increasing or decreasing in
any material way.

Capital Resources.  The Partnership does not have, nor does it
expect to have, any capital assets.  Redemptions of units of
limited partnership interest (?Unit(s)?) in the future will affect
the amount of funds available for investments in futures,
forwards, and options in subsequent periods.  It is not possible
<page> to estimate the amount, and therefore the impact, of future
outflows of Units.

There are no known material trends, favorable or unfavorable, that
would affect, nor any expected material changes to, the
Partnership?s capital resource arrangements at the present time.

Off-Balance Sheet Arrangements and Contractual Obligations.  The
Partnership does not have any off-balance sheet arrangements, nor
does it have contractual obligations or commercial commitments to
make future payments that would affect its liquidity or capital
resources.

Results of Operations
General.  The Partnership?s results depend on the Trading Advisor
and the ability of the Trading Advisor?s trading program to take
advantage of price movements in the futures, forward, and options
markets.  The following presents a summary of the Partnership?s
operations for the three month periods ended March 31, 2007, and
2006, and a general discussion of its trading activities during
each period.  It is important to note, however, that the Trading
Advisor trades in various markets at different times and that
prior activity in a particular market does not mean that such
market will be actively traded by the Trading Advisor or will be
profitable in the future. Consequently, the results of operations
of the Partnership are difficult to discuss other than in the
<page> context of the Trading Advisor?s trading activities on
behalf of the Partnership during the period in question. Past
performance is no guarantee of future results.

The Partnership?s results of operations set forth in the
financial statements on pages 2 through 13 of this report are
prepared in accordance with accounting principles generally
accepted in the United States of America, which require the use
of certain accounting policies that affect the amounts reported
in these financial statements, including the following:  The
contracts the Partnership trades are accounted for on a trade-
date basis and marked to market on a daily basis. The difference
between their cost and market value is recorded on the
Consolidated Statements of Operations as ?Net change in
unrealized trading profit (loss)? for open (unrealized)
contracts, and recorded as ?Realized trading profit (loss)? when
open positions are closed out.  The sum of these amounts
constitutes the Partnership?s trading results.  The market value
of a futures contract is the settlement price on the exchange on
which that futures contract is traded on a particular day.  The
value of a foreign currency forward contract is based on the spot
rate as of the close of business.  Interest income, as well as
management fees, incentive fees, brokerage fees, and transaction
fees and costs of the Partnership are recorded on an accrual
basis.

<page> Demeter believes that, based on the nature of the
operations of the Partnership, no assumptions relating to the
application of critical accounting policies other than those
presently used could reasonably affect reported amounts.

For the Quarter Ended March 31, 2007
The Partnership recorded total trading results including interest
income totaling $(108,446), expenses totaling $211,491, and
minority interest of $(3,524), resulting in a net loss of
$316,413 for the quarter ended March 31, 2007.  The Partnership?s
net asset value per Unit decreased from $1,909.85 at December 31,
2006, to $1,865.60 at March 31, 2007.

The most significant trading losses of approximately 1.4% were
recorded within the global stock index sector, primarily during
February and early March, from long positions in U.S., European,
and Pacific Rim stock index futures as prices reversed sharply
lower after a massive sell-off in the global equity markets that
began on February 27, 2007 following comments from former U.S.
Federal Reserve Chairman Alan Greenspan that the U.S. economy
could be due for a recession.  In addition, concerns that tighter
credit conditions in China and Japan might dampen global growth
first sent Chinese stock markets plunging before the sell-off
spread to other equity markets.  Furthermore, global equity
prices were negatively affected by sub-prime loan delinquency
concerns in the United States.  Smaller losses were experienced
<page> during March from newly established short positions in
Japanese equity index futures as prices drifted higher on
investor sentiment that markets had been oversold in recent
weeks.  Additional losses of approximately 0.7% were experienced
in the global interest rate futures markets primarily during
February from short positions in German, U.S., and Australian
fixed-income futures as prices moved higher in a worldwide
flight-to-quality after the aforementioned sell-off in the global
equity markets.  During March, newly established long positions
in German and U.S. interest rate futures incurred further losses
as prices declined later in the month amid reduced demand for the
?safe-haven? of fixed-income investments amid the stabilization
of the global equity markets after investors concluded that
markets had been oversold in recent weeks.  Furthermore, German
interest rate futures were pressured lower on strong economic
data out of Germany, while U.S. interest rate prices declined
after a stronger than expected government jobs report.  Smaller
losses of approximately 0.3% were incurred in the currency sector
during January and March from long positions in the euro versus
the Norwegian krone as the value of the Norwegian krone
strengthened relative to most of its major rivals after stronger
than expected economic data was reported out of Norway.
Meanwhile, losses were recorded during January from both short
and long positions in the South African rand versus the U.S.
dollar as the value of the South African rand moved without
consistent direction.  Additional losses in the currency markets
<page> were experienced from long positions in the Mexican peso
versus the U.S. dollar during January and February as the value
of the U.S. dollar moved higher on speculation that the U.S.
Federal Reserve would not cut interest rates in the near-term.
In addition, the value of the Mexican peso was pulled lower in
tandem with falling U.S. equity markets.  Losses of approximately
0.3% were recorded in the agricultural markets from short
positions in lean hog futures as prices increased during January
on worries that freezing temperatures might negatively impact
supply.  Further losses were experienced during March from both
short and long positions in lean hog futures as prices moved
without consistent direction.  Elsewhere in the agricultural
complex, long positions in orange juice futures resulted in
losses during January as prices declined on technically-based
selling.  During February, additional losses were incurred from
newly established short positions in orange juice futures as
prices reversed higher due to freezing weather across much of the
growing regions of the United States.  A portion of the
Partnership?s losses for the quarter was offset by gains of
approximately 0.5% in the metals sector, primarily during
February and March, from long positions in nickel futures as
prices moved higher on speculation that low stockpiles and supply
disruptions might create a supply shortage. Short positions in
copper futures experienced further gains during January as prices
weakened due to an overabundance in supply by producer countries.
During March, gains were recorded from long positions in copper
<page> futures as prices moved higher on news that China?s
industrial production increased at a strong pace in January and
February.  Elsewhere in the metals markets, smaller gains were
experienced during March from short positions in silver and gold
futures as prices moved lower on technically-based selling.
Additional gains of approximately 0.2% were experienced in the
energy markets primarily during March from long futures positions
in gasoline and Brent crude oil as prices increased after data
indicated higher U.S. fuel consumption.  In addition, prices
moved higher amid rising geopolitical concerns in the Middle East
after the United Nations Security Council voted unanimously to
increase sanctions against Iran.  Prices also rose on news that
Iran had captured 15 members of the British Royal Navy in the
Persian Gulf, adding to investor worries about the stability of
the world?s oil supply in the region.

For the Quarter Ended March 31, 2006
The Partnership recorded total trading results including interest
income totaling $303,629, expenses totaling $246,526, and
minority interest of $301, resulting in net income of $56,802
for the quarter ended March 31, 2006.  The Partnership?s net
asset value per Unit increased from $1,895.39 at December 31,
2005, to $1,902.16 at March 31, 2006.

The most significant trading gains of approximately 1.5% were
recorded in the global stock index futures markets from long
<page> positions in S&P 500 Index futures as prices moved higher
after a weaker than expected December U.S. jobs report raised
hopes the U.S. Federal Reserve might end its cycle of interest
rate hikes sooner rather than later.  Prices were also pressured
higher on strong earnings announcements from several U.S. bell
weather companies.  Additional gains of approximately 0.3% were
experienced in the metals markets, during January and March, from
long futures positions in copper and zinc as prices strengthened
amid weak supplies, forecasts for continued buying by China, and
acceleration in demand from Japan, Europe, and the U.S.
Elsewhere in the metals markets, gains were recorded from long
futures positions in silver and gold as precious metals prices
moved higher on persistent demand from foreign central banks.
Silver prices were also pressured higher after news that a
silver-backed Exchange Traded Fund would soon launch and create
greater investment interest in the metal.  A portion of the
Partnership?s overall gains for the quarter was offset by losses
of approximately 0.4% in global interest rate sector, primarily
during January, from both long and short positions in European,
Australian, and Canadian fixed-income futures as prices moved
without consistent direction amid uncertainty regarding the
interest rate policy of the European Central Bank, the Reserve
Bank of Australia, and the Bank of Canada.  Additional losses of
approximately 0.4% were incurred in the currency sector during
February from short positions in the euro versus the U.S. dollar,
as well as from outright short positions in the U.S. dollar
<page> index, after the U.S. dollar?s value was lifted by
expectations for additional increases in U.S. interest rates.
Further losses in the currency sector were incurred during March
from short positions in the euro and the Swiss franc relative to
the U.S. dollar as the value of these European currencies moved
higher after the release of generally positive economic data from
the Euro-Zone reinforced expectations that European interest
rates would continue to rise. The value of the euro then reversed
lower against the U.S. dollar toward the second half of the month
amid negative economic data regarding European consumer spending,
resulting in losses from newly established long positions.
Smaller losses of approximately 0.3% were experienced in the
energy markets from long futures positions in crude oil and its
related products as prices declined during February after an
announcement by Chinese government authorities that China would
place an emphasis on prospecting alternative energy sources in
the future, reports of larger than expected supplies from the
International Energy Agency, and mild weather in the U.S.
Northeast.  Further losses in the energy markets were recorded
during March from short positions in crude oil and unleaded
gasoline futures as prices strengthened early in the month on
supply fears fueled by news of geopolitical tensions in Nigeria
and Iran.






<page> Item 3.QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT
MARKET RISK
Introduction
The Partnership is a commodity pool engaged primarily in the
speculative trading of futures, forwards, and options.  The
market-sensitive instruments held by the Partnership are acquired
for speculative trading purposes only and, as a result, all or
substantially all of the Partnership?s assets are at risk of
trading loss.  Unlike an operating company, the risk of market-
sensitive instruments is inherent to the primary business
activity of the Partnership.

The futures, forwards, and options traded by the Partnership
involve varying degrees of related market risk.  Market risk is
often dependent upon changes in the level or volatility of
interest rates, exchange rates, and prices of financial
instruments and commodities, factors that result in frequent
changes in the fair value of the Partnership?s open positions,
and consequently in its earnings, whether realized or unrealized,
and cash flow.  Gains and losses on open positions of exchange-
traded futures, exchange-traded forward, and exchange-traded
futures-styled options contracts are settled daily through
variation margin.  Gains and losses on off-exchange-traded
forward currency contracts are settled upon termination of the
contract.  However, the Partnership is required to meet margin
requirements equal to the net unrealized loss on open forward
<page> currency contracts in the Partnership accounts with the
counterparty, which is accomplished by daily maintenance of the
cash balance in a custody account held at Morgan Stanley DW for
the benefit of MS&Co.

The Partnership?s total market risk may increase or decrease as
it is influenced by a wide variety of factors, including, but not
limited to, the diversification among the Partnership?s open
positions, the volatility present within the markets, and the
liquidity of the markets.

The face value of the market sector instruments held by the
Partnership is typically many times the applicable margin
requirements.  Margin requirements generally range between 2% and
15% of contract face value.  Additionally, the use of leverage
causes the face value of the market sector instruments held by
the Partnership typically to be many times the total
capitalization of the Partnership.

The Partnership?s past performance is no guarantee of its future
results.  Any attempt to numerically quantify the Partnership?s
market risk is limited by the uncertainty of its speculative
trading.  The Partnership?s speculative trading and use of
leverage may cause future losses and volatility (i.e., ?risk of
ruin?) that far exceed the Partnership?s experience to date under
the ?Partnership?s Value at Risk in Different Market Sectors?
<page> section and significantly exceed the Value at Risk (?VaR?)
tables disclosed.

Limited partners will not be liable for losses exceeding the
current net asset value of their investment.

Quantifying the Partnership?s Trading Value at Risk
The following quantitative disclosures regarding the Partner-
ship?s market risk exposures contain ?forward-looking statements?
within the meaning of the safe harbor from civil liability
provided for such statements by the Private Securities Litigation
Reform Act of 1995 (set forth in Section 27A of the Securities
Act of 1933 and Section 21E of the Securities Exchange Act of
1934).  All quantitative disclosures in this section are deemed
to be forward-looking statements for purposes of the safe harbor,
except for statements of historical fact.

The Partnership accounts for open positions on the basis of mark
to market accounting principles.  Any loss in the market value of
the Partnership?s open positions is directly reflected in the
Partnership?s earnings and cash flow.

The Partnership?s risk exposure in the market sectors traded by
the Trading Advisor is estimated below in terms of VaR. The
Partnership estimates VaR using a model based upon historical
simulation (with a confidence level of 99%) which involves <page>
constructing a distribution of hypothetical daily changes in the
value of a trading portfolio.  The VaR model takes into account
linear exposures to risk including equity and commodity prices,
interest rates, foreign exchange rates, and correlation among
these variables.  The hypothetical changes in portfolio value are
based on daily percentage changes observed in key market indices
or other market factors (?market risk factors?) to which the
portfolio is sensitive.  The one-day 99% confidence level of the
Partnership?s VaR corresponds to the negative change in portfolio
value that, based on observed market risk factors, would have been
exceeded once in 100 trading days, or one day in 100.  VaR
typically does not represent the worst case outcome.  Demeter uses
approximately four years of daily market data (1,000 observations)
and re-values its portfolio (using delta-gamma approximations) for
each of the historical market moves that occurred over this time
period.  This generates a probability distribution of daily
?simulated profit and loss? outcomes.  The VaR is the appropriate
percentile of this distribution.  For example, the 99% one-day VaR
would represent the 10th worst outcome from Demeter?s simulated
profit and loss series.

The Partnership?s VaR computations are based on the risk
representation of the underlying benchmark for each instrument or
contract and do not distinguish between exchange and non-exchange
dealer-based instruments.  They are also not based on exchange
and/or dealer-based maintenance margin requirements.
<page> VaR models, including the Partnership?s, are continually
evolving as trading portfolios become more diverse and modeling
techniques and systems capabilities improve.  Please note that the
VaR model is used to numerically quantify market risk for
historic reporting purposes only and is not utilized by either
Demeter or the Trading Advisor in their daily risk management
activities.  Please further note that VaR as described above may
not be comparable to similarly-titled measures used by other
entities.

The Partnership?s Value at Risk in Different Market Sectors
The following table indicates the VaR associated with the
Partnership?s open positions as a percentage of total Net Assets
by primary market risk category at March 31, 2007 and 2006. At
March 31, 2007 and 2006, the Partnership?s total capitalization
was approximately $13 million and $16 million, respectively.

Primary Market             March 31, 2007         March 31, 2006
Risk Category	  	        Value at Risk         Value at Risk

Interest Rate	(0.79)%	(0.89)%
Equity	(0.75)	(1.56)
Currency                  	(0.22)	(0.09)
Commodity           	(0.17)            	(0.20)
Aggregate Value at Risk          (1.17)%		(2.10)%


The VaR for a market category represents the one-day downside
risk for the aggregate exposures associated with this market
<page> category.  The Aggregate Value at Risk listed above
represents the VaR of the Partnership?s open positions across all
the market categories, and is less than the sum of the VaRs for
all such market categories due to the diversification benefit
across asset classes.

Because the business of the Partnership is the speculative trading
of futures, forwards, and options, the composition of its trading
portfolio can change significantly over any given time period, or
even within a single trading day.  Such changes could positively
or negatively materially impact market risk as measured by VaR.

The table below supplements the quarter-end VaR set forth above
by presenting the Partnership?s high, low, and average VaR, as a
percentage of total Net Assets for the four quarter-end reporting
periods from April 1, 2006, through March 31, 2007.

Primary Market Risk Category        High      Low      Average
Interest Rate	(1.38)%	(0.35)%	(0.85)%
Equity	(1.12)	(0.57)	(0.84)
Currency	(0.22)	(0.04)	(0.15)
Commodity	(0.20)	(0.12)	(0.17)
Aggregate Value at Risk	(1.41)%	(0.75)%	(1.17)%


Limitations on Value at Risk as an Assessment of Market Risk

VaR models permit estimation of a portfolio?s aggregate market
risk exposure, incorporating a range of varied market risks,
<page> reflect risk reduction due to portfolio diversification or
hedging activities, and can cover a wide range of portfolio
assets.  However, VaR risk measures should be viewed in light of
the methodology?s limitations, which include, but may not be
limited to the following:
*	past changes in market risk factors will not always result in
accurate predictions of the distributions and correlations of
future market movements;
*	changes in portfolio value caused by market movements may
differ from those of the VaR model;
*	VaR results reflect past market fluctuations applied to
current trading positions while future risk depends on future
positions;
*	VaR using a one-day time horizon does not fully capture the
market risk of positions that cannot be liquidated or hedged
within one day; and
*	the historical market risk factor data used for VaR
estimation may provide only limited insight into losses that
could be incurred under certain unusual market movements.

In addition, the VaR tables above, as well as the past performance
of the Partnership, give no indication of the Partnership?s
potential ?risk of ruin?.

The VaR tables provided present the results of the Partnership?s
VaR for each of the Partnership?s market risk exposures and on an
<page> aggregate basis at March 31, 2006, and for the four
quarter-end reporting periods from April 1, 2006 through March 31,
2007.  VaR is not necessarily representative of the Partnership?s
historic risk, nor should it be used to predict the Partnership?s
future financial performance or its ability to manage or monitor
risk.  There can be no assurance that the Partnership?s actual
losses on a particular day will not exceed the VaR amounts
indicated above or that such losses will not occur more than once
in 100 trading days.

Non-Trading Risk
The Partnership has non-trading market risk on its foreign cash
balances.  These balances and any market risk they may represent
are immaterial.

The Partnership also maintains a substantial portion of its
available assets in cash at MS&Co. (Morgan Stanley DW, prior to
April 1, 2007); as of March 31, 2007, such amount is equal to
approximately 97% of the Partnership?s net asset value.  A decline
in short-term interest rates would result in a decline in the
Partnership?s cash management income.  This cash flow risk is not
considered to be material.

Materiality, as used throughout this section, is based on an
assessment of reasonably possible market movements and any
associated potential losses, taking into account the leverage,
<page> optionality, and multiplier features of the Partnership?s
market-sensitive instruments, in relation to the Partnership?s Net
Assets.

Qualitative Disclosures Regarding Primary Trading Risk Exposures
The following qualitative disclosures regarding the Partnership?s
market risk exposures ? except for (A) those disclosures that are
statements of historical fact and (B) the descriptions of how the
Partnership manages its primary market risk exposures ? constitute
forward-looking statements within the meaning of Section 27A of
the Securities Act and Section 21E of the Securities Exchange Act.
The Partnership?s primary market risk exposures, as well as the
strategies used and to be used by Demeter and the Trading Advisor
for managing such exposures, are subject to numerous
uncertainties, contingencies and risks, any one of which could
cause the actual results of the Partnership?s risk controls to
differ materially from the objectives of such strategies.
Government interventions, defaults and expropriations, illiquid
markets, the emergence of dominant fundamental factors, political
upheavals, changes in historical price relationships, an influx of
new market participants, increased regulation, and many other
factors could result in material losses, as well as in material
changes to the risk exposures and the risk management strategies
of the Partnership.  Investors must be prepared to lose all or
substantially all of their investment in the Partnership.

<page> The following were the primary trading risk exposures of
the Partnership at March 31, 2007, by market sector.  It may be
anticipated, however, that these market exposures will vary
materially over time.

Interest Rate.  The largest market exposure of the Partnership at
March 31, 2007, was to the global interest rate sector.  Exposure
was primarily spread across the New Zealand, U.S., European,
Australian, and Japanese interest rate sectors.  Interest rate
movements directly affect the price of the sovereign bond futures
positions held by the Partnership and indirectly affect the value
of its stock index and currency positions.  Interest rate
movements in one country, as well as relative interest rate
movements between countries, materially impact the Partnership?s
profitability.  The Partnership?s interest rate exposure is
generally to interest rate fluctuations in the U.S. and the other
G-7 countries? interest rates.  The G-7 countries consist of
France, the U.S., Britain, Germany, Japan, Italy, and Canada.
However, the Partnership also takes futures positions in the
government debt of smaller countries ? e.g., New Zealand and
Australia.  Demeter anticipates that the G-7 countries? interest
rates, as well as New Zealand and Australian interest rates, will
remain the primary interest rate exposures of the Partnership for
the foreseeable future.  The speculative futures positions held
by the Partnership range from short to long-term instruments.
<page> Consequently, changes in short, medium, or long-term
interest rates may have an effect on the Partnership.

Equity.  The second largest market exposure of the Partnership at
March 31, 2007, was to the global stock index sector, primarily
to equity price risk in the G-7 countries.  The stock index
futures traded by the Partnership are by law limited to futures
on broadly-based indices.  At March 31, 2007, the Partnership?s
primary exposures were to the S&P 500 (U.S.), NIKKEI 225 (Japan),
IBEX 35 (Spain), NASDAQ 100 (U.S.), and RUSSELL 2000 (U.S.) stock
indices.  The Partnership is primarily exposed to the risk of
adverse price trends or static markets in the U.S., Japanese, and
European stock indices.  Static markets would not cause major
market changes, but would make it difficult for the Partnership
to avoid trendless price movements, resulting in numerous small
losses.

Currency.  At March 31, 2007, the Partnership had market exposure
to the currency sector.  Exposure was to exchange rate
fluctuations, primarily fluctuations which disrupt the historical
pricing relationships between different currencies and currency
pairs.  Interest rate changes, as well as political and general
economic conditions influence these fluctuations.  The
Partnership trades a large number of currencies, including cross-
rates - i.e., positions between two currencies other than the
U.S. dollar.  Outright positions consist of the U.S. dollar vs.
<page> other currencies.  These other currencies include major
and minor currencies.  Demeter does not anticipate that the risk
associated with the Partnership?s currency trades will change
significantly in the future.

Commodity.
Soft Commodities and Agriculturals.  The third largest
market exposure of the Partnership at March 31, 2007, was to
the markets that comprise these sectors.  Most of the
exposure was to the sugar, live cattle, lean hogs, soybean
meal, feeder cattle, corn, and coffee markets.  Supply and
demand inequalities, severe weather disruptions, and market
expectations affect price movements in these markets.

Energy.  At March 31, 2007, the Partnership had market
exposure to the energy sector.  The Partnership?s energy
exposure was shared primarily by futures contracts in oil
related products.  Price movements in these markets result
from geopolitical developments, particularly in the Middle
East, as well as weather patterns, and other economic
fundamentals.  Significant profits and losses, which have
been experienced in the past, are expected to continue to be
experienced in the future.

Metals.  At March 31, 2007, the Partnership had market
exposure in the metals sector.  The Partnership?s metals
<page> exposure was to fluctuations in the price of base
metals, such as copper.  Economic forces, supply and demand
inequalities, geopolitical factors, and market expectations
influence price movements in these markets.  The Trading
Advisor utilizes its trading system(s) to take positions when
market opportunities develop, and Demeter anticipates that
the Partnership will continue to do so.

Qualitative Disclosures Regarding Non-Trading Risk Exposure
The following was the only non-trading risk exposure of the
Partnership at March 31, 2007:

Foreign Currency Balances.  The Partnership?s primary
foreign currency balances at March 31, 2007, were in euros,
New Zealand dollars, British pounds, Australian dollars,
Japanese yen, and Swiss francs.  The Partnership controls
the non-trading risk of foreign currency balances by
regularly converting them back into U.S. dollars upon
liquidation of their respective positions.

Qualitative Disclosures Regarding Means of Managing Risk Exposure
The Partnership and the Trading Advisor, separately, attempt to
manage the risk of the Partnership?s open positions in essentially
the same manner in all market categories traded.  Demeter attempts
to manage market exposure by diversifying the Partnership?s assets
among different market sectors and trading approaches, and by
<page> monitoring the performance of the Trading Advisor daily.
In addition, the Trading Advisor establishes diversification
guidelines, often set in terms of the maximum margin to be
committed to positions in any one market sector or market-
sensitive instrument.

Demeter monitors and controls the risk of the Partnership?s non-
trading instruments, cash.  Cash is the only Partnership
investment directed by Demeter, rather than the Trading Advisor.

Item 4.  CONTROLS AND PROCEDURES
(a)	As of the end of the period covered by this quarterly report,
the President and Chief Financial Officer of Demeter, the
general partner of the Partnership, have evaluated the
effectiveness of the Partnership?s disclosure controls and
procedures (as defined in Rules 13a-15(e) and 15d-15(e) of
the Exchange Act), and have judged such controls and
procedures to be effective.

(b)	There have been no material changes during the period
covered by this quarterly report in the Partnership?s
internal control over financial reporting (as defined in
Rules 13a-15(f) and 15d-15(f) of the Exchange Act) or in
other factors that could significantly affect these controls
subsequent to the date of their evaluation.

<page> Item 4T.  CONTROLS AND PROCEDURES
Not applicable.
<page> PART II.  OTHER INFORMATION


Item 1A.  RISK FACTORS

Information regarding risk factors appears in Item 2.
?Management?s Discussion and Analysis of Financial Condition and
Results of Operations? and Item 3. ?Quantitative and Qualitative
Disclosures about Market Risk? of this Form 10-Q.  There have been
no other material changes from the risk factors previously
referenced in the Partnership?s Report on Form 10-K for the fiscal
year ended December 31, 2006.


Item 6.  EXHIBITS

31.01	Certification of President of Demeter Management
Corporation, the general partner of the Partnership,
pursuant to Section 302 of the Sarbanes-Oxley Act of
2002.
31.02	Certification of Chief Financial Officer of Demeter
Management Corporation, the general partner of the
Partnership, pursuant to Section 302 of the Sarbanes-
Oxley Act of 2002.
32.01	Certification of President of Demeter Management
Corporation, the general partner of the Partnership,
pursuant to 18 U.S.C. Section 1350, as adopted pursuant
to Section 906 of the Sarbanes-Oxley Act of 2002.
32.02	Certification of Chief Financial Officer of Demeter
Management Corporation, the general partner of the
Partnership, pursuant to 18 U.S.C. Section 1350, as
adopted pursuant to Section 906 of the Sarbanes-Oxley Act
of 2002.





<page>



SIGNATURE



Pursuant to the requirements of the Securities Exchange Act of
1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned thereunto duly authorized.




                      Morgan Stanley Principal Plus Fund L.P.
                      (Registrant)

                      By:   Demeter Management Corporation
                            (General Partner)

May 15, 2007          By:  /s/Lee Horwitz
                              Lee Horwitz
                              Chief Financial Officer




The General Partner which signed the above is the only party
authorized to act for the Registrant.  The Registrant has no
principal executive officer, principal financial officer,
controller, or principal accounting officer and has no Board of
Directors.
















DEAN WITTER PRINCIPAL PLUS FUND L.P.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
6