Exhibit 10.6
 KEITHLEY INSTRUMENTS, INC.
SUPPLEMENTAL DEFERRAL PLAN
 Amended and Restated January 1, 2008




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TABLE OF CONTENTS
 PageARTICLE ONE
    
    
    4ARTICLE TWO
    
    
    4ARTICLE THREE
    
    
    5ARTICLE FOUR
    
    
    6ARTICLE FIVE
    
    
    7ARTICLE SIX
    
    
    8ARTICLE SEVEN
    
    
    9ARTICLE EIGHT
    
    
    9ARTICLE NINE
    
    
    10ARTICLE TEN
    
    
    10ARTICLE ELEVEN
    
    
    11ARTICLE TWELVE
    
    
    11ARTICLE THIRTEEN
    
    
    13ARTICLE FOURTEEN
    
    
    14ARTICLE FIFTEEN
    
    
    14ARTICLE SIXTEEN
    
    
    14ARTICLE SEVENTEEN
    
    
    15ARTICLE EIGHTEEN
    
    
    15
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KEITHLEY INSTRUMENTS, INC.
SUPPLEMENTAL DEFERRAL PLAN
(Amended and Restated January 1, 2008)
 THIS AMENDED AND RESTATED KEITHLEY INSTRUMENTS, INC. SUPPLEMENTAL DEFERRAL PLAN
 WITNESSETH:
 WHEREAS,
 WHEREAS,
 WHEREAS,
 WHEREAS,
 NOW, THEREFORE,
 DEFINITIONS:
 Account .




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Affiliate .
 Calendar Year .
 Compensation .
 Corporation .
 Early Retirement Date .
 Effective Date .
 Election to Defer .
 Eligible Individual .
 ERISA .
  2




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Minimum Eligible Compensation Level .
 Normal Retirement Date .
 Participant .
 Participant Annual Deferral .
 Plan .
 Plan Administrator .
 Plan Year .
 Separation from Service .
  Specified Employee .
  3




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ARTICLE ONE
 1.01 Eligibility .
 1.02 Deferral Election .
 1.03 Crediting Corporate Amounts .
 ARTICLE TWO
 2.01 Responsibility for Administration of the Plan .
  4




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2.02 Information from Corporation .
 2.03 Investment .
 ARTICLE THREE
 3.01 Vesting of Plan Interests .
 Completed Years Of Plan Participation
    
    Vested PercentageLess than 1
    
    
    0
    %1 but less than 2
    
    
    33
    %2 but less than 3
    
    
    67
    %3 or more
    
    
    100
    %
   5




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3.02 Vesting Upon Change in Control .
   ARTICLE FOUR
 4.01 Earnings or Losses on Deferred Amounts .
  6




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ARTICLE FIVE
 5.01 Election to Defer Compensation .
 5.02 Transfer, Consolidation of Corporate Interests .
 5.03 Petition to Cease Deferrals Mid-Year .
  7




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ARTICLE SIX
 6.01 Retirement and Termination Benefit .
 th
 6.02 Accelerated Payments .
  th
  8




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ARTICLE SEVEN
 7.01 Disability Benefit .
 ARTICLE EIGHT
 8.01 Death Benefit Prior to Commencement of Benefits . 
 8.02 Death Benefit After Commencement of Benefits .
  9




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ARTICLE NINE
 9.01 Termination Benefits .
 th
 9.02 Termination for Cause . 
 ARTICLE TEN
 10.01 Application for Unforeseeable Emergency Distribution .
 10.02 Amount of Distribution .
  10




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10.03 Unforeseeable Emergency .
 10.04 Further Deferrals .
 10.05 Rules Adopted by Plan Administrator .
 10.06 Limit on Number of Distributions Due to Unforeseeable Emergency .
 10.07 In-Service Distribution .
 10.08 Timing of Distribution .
 10.09 Amount of In-Service Distribution .
 ARTICLE ELEVEN
 11.01 Beneficiary Designation .
 ARTICLE TWELVE
 12.01 No Trust Created .
  11




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12.02 Benefits Payable Only From General Corporate Assets: (Unsecured
General Creditor Status of Participant) .
 12.03 No Contractual Relationship .
 12.04 Interests Not Transferable .
 12.05 Indemnification Against Third Party Claims .
 12.06 Hold Harmless of Corporate Agents .
  12




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12.07 Taxes; No Guarantee of Tax Consequences .
 ARTICLE THIRTEEN
 13.01 Claim Procedure .
 13.02 Claim Decision .
   any
   13.03 Request for Review .
  13




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13.04 Review of Decision .
 13.05 Effect of Reviewed Decision . 
 ARTICLE FOURTEEN
 14.01 Amendment .
 ARTICLE FIFTEEN
 15.01 Notice .
 ARTICLE SIXTEEN
 16.01 Facility of Payment .
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ARTICLE SEVENTEEN
 17.01 Board Authority .
 ARTICLE EIGHTEEN
 18.01 Governing Law .
 18.02 Entire Agreement .
 18.03 Transition Relief for Payment Election .
 18.04 Pre-2005 Deferrals .
 18.05 Code Section 409A Compliance
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IN WITNESS WHEREOF,
 KEITHLEY INSTRUMENTS, INC.By:
    /s/ Mark J. PlushTitle:  Vice President and Chief Financial OfficerDate: December 31, 2008  16