EXHIBIT 10.21

March 28, 2002

Mr. Ike Udechuku 2436 Clay Street San Francisco, CA 94115

Dear Ike:

This letter is to confirm the agreement (the "Agreement") between you and Align
Technology, Inc. (the "Company") regarding your separation from employment with
the Company.

 1. Your separation from the Company will be effective on February 28, 2002 (the
    "Separation Date") and you will not be required to report to work after
    today.
 2. You will be paid a lump sum amount equal to three (3) months of your current
    base salary of $200,000.00, less all applicable deductions and withholdings,
    forty-eight (48) hours following our signing and dating this Agreement.
 3. You understand and agree that all Company-sponsored benefits terminate upon
    your Separation Date. Should you be eligible and choose to continue your
    medical benefits under COBRA, the Company will pay your monthly COBRA
    premiums for you through the earlier of three (3) months, or such time as
    you become eligible for health care coverage under a new employer plan. You
    must notify the Company when you become covered under another employer's
    plan. Thereafter, continued coverage under COBRA will be at your own
    expense, subject to COBRA terms, conditions, and eligibility requirements.
 4. Option/Share Vesting Benefit: You shall be given an additional three (3)
    months of service credit for the purposes of option vesting or share vesting
    ("the Acceleration"), as the case may be. With the exception of this service
    credit, each of your option/share grants shall otherwise continue to be
    governed and enforced under the terms of the plan under which the
    option/share grant was made, and the applicable stock option and/or stock
    purchase agreement.
     a. You acknowledge and agree that each of your existing stock options with
        the Company is referenced in the following table (your "Options"), and
        that your rights to Company Common Stock under each such option,
        including the Acceleration, is reflected in the "Vested Shares " column
        below:

Option No.

Option Date

Plan/
Type

Price per Share (post-split)

Shares Granted (post-split)

Post-split

Vested Shares

Post-split

Unvested Shares

00000446

08/08/00

1997/ISO

$2.13 ($1.0650)

46,948 (93,896)

43,035

50,861

00000509

08/08/00

1997/NQ

$2.13 ($1.0650)

60,052 (120,104)

55,047

65,057

00000591

09/29/00

1997/NQ

$2.13 ($1.0650)

10,214 (20,428)

8,086

12,342

00001158

11/13/00

1997/NQ

$2.13 ($1.0650)

10,000 (20,000)

7,500

12,500

 b. You further acknowledge and agree that you early-exercised Option Nos.
    00000446, 00000509, 00000591, 00001158 as to all shares using four (4)
    promissory notes, as described below, and that including the Acceleration,
    140,760 of such shares are Unvested Shares which are now subject to the
    Company's right of repurchase. The Company has notified you, and hereby
    reaffirms that notification, of its intent to repurchase all such 140,760
    Unvested Shares under Option Nos. 00000446, 00000509, 00000591, 00001158 at
    the purchase price of $1.0650 per share. This repurchase will be effected
    through the cancellation of $149,909.40 of the $270,965.82 you owe the
    Company due to your four (4) promissory notes.
 c. You further acknowledge and agree that, taking into account the repurchase
    of your Unvested Shares described above, you owe the Company $156,528.11
    ($121,056.42 of which is the remaining balance of the four (4) notes and
    $35,471.69 of which is accrued interest). These notes were full-recourse and
    were secured by the Company Common Stock underlying your Options. All four
    (4) of these notes are currently in default, due to your failure to pay the
    accrued interest of $26,975.50 due on November 13, 2002. The Company has not
    yet received this interest payment from you and is taking the following
    action pursuant to the terms of the Note and the corresponding Stock Pledge
    Agreement, dated November 13, 2000 (the "Stock Pledge Agreement"), which you
    entered into with the Company.

    Pursuant to Section 5A of the Note and Section 10 of the Stock Pledge
    Agreement, the Company proposes to retain and cancel Shares held as
    Collateral under the Stock Pledge Agreement in an amount sufficient in value
    to cover the full amount of the Debt you owe the Company, plus all interest
    accrued on the Debt to the date first set forth above. The Shares so
    retained and cancelled will be valued at the closing price of the Company's
    common stock as reported by The Wall Street Journal as of your separation
    date. Any remaining Shares will be released as Collateral under the terms of
    the Pledge Agreement. Each of your Options shall continue to be governed by
    the written terms of the Align Technology, Inc. 1997 Equity Incentive Plan,
    and the existing stock option, stock purchase, and/or stock issuance
    agreement(s) and any addenda or waivers thereto, now existing between you
    and the Company (collectively, the "Option Agreements").

    The Company has notified you, and hereby reaffirms that notification, of its
    intent to retain and cancel 36,831 Vested Shares under Option Nos. 00000446,
    00000509, 00000591, 00001158 at the February 28, 2002 market price of $4.25
    per share for payment of the remaining outstanding balance of $156,528.11
    you owe the Company due to your four (4) promissory notes.

 d. You agree that you have no rights to any Company equity under any Company
    plan, policy or practice, except as expressly set out in this Paragraph 4
    and your Option Agreements.

 1.  You agree that when you were hired, the Company advanced you a payment
     against unearned wages in the amount of $95,000.00 (the "Advance"). The
     Advance was due on demand but in no event later than September 19, 2001.
     The advance amount of $95,000 and accrued interest of $8,216.12 will be
     forgiven. The forgiveness of a debt must be reported as taxable income on
     your 2002 W-2. Align will pay the FICA and Medicare taxes for you, however,
     the tax payment will also be reflected on your 2002 W-2 as taxable income.
 2.  You agree that as of your Separation Date you have already been paid for
     all of your accrued but unused vacation, salary and commissions earned
     through February 28, 2002
 3.  In consideration for receiving the severance payments and benefits
     described above, and for other good and sufficient consideration as
     reflected in this Agreement and which you hereby acknowledge, you waive and
     release and promise never to assert any claims, whether or not now known,
     against Align Technology and its current and former predecessors,
     successors, subsidiaries, officers, directors, agents, employees and
     assigns, with respect to any matter arising out of or connected with your
     employment with the Company or the termination of that employment,
     including without limitation, claims of wrongful discharge, emotional
     distress, defamation, breach of contract, breach of the covenant of good
     faith and fair dealing, any claims of discrimination based on sex, age,
     race, national origin, or any other basis, under Title VII of the Civil
     Rights Act of 1964, as amended, any violation of California Labor Code, the
     California Fair Employment and Housing Act, California Constitution, the
     Equal Pay Act of 1963, the Americans with Disabilities Act, and any other
     laws or regulations relating to employment. The only claims not waived by
     you under this Agreement include claims for:
      a. workers' compensation insurance benefits under the terms of any
         workers' compensation insurance policy or fund;
      b. unemployment or any state disability insurance benefits pursuant to the
         terms of applicable state law; and
      c. continued participation in certain of the Company's group benefit plans
         pursuant to the federal law known as COBRA.

 4.  You expressly waive and release any and all rights and benefits under
     Section 1542 of the Civil Code of the State of California, or any analogous
     law of any other state, which reads as follows: "A general release does not
     extend to claims which the creditor does not know or suspect to exist in
     his favor at the time of executing the release, which, if known by him,
     must have materially affected his settlement with the debtor."
 5.  You agree that you do not have any charges, claims, administrative
     complaints or lawsuits of any kind pending against the Company, and you
     represent and warrant that you do not have any basis to file, nor intent to
     file, any such charge, claim, complaint, or lawsuit.
 6.  You and the Company agree that neither you nor the Company will disclose to
     others the fact or terms of this letter, except that you may disclose such
     information to your attorney or accountant in order for such individuals to
     render services to you.
 7.  Nothing contained in this Agreement shall constitute or be treated as an
     admission by you or the Company of liability, of any wrongdoing, or of any
     violation of law.
 8.  At all times in the future, you will remain bound by Company's Proprietary
     Information and Inventions Agreement signed by you on August 21, 2000, a
     copy of which is attached.
 9.  You agree not to make any derogatory, disparaging or negative statements
     about the Company, its products, or employees.
 10. You agree that except as expressly provided in this Agreement, this
     Agreement renders null and void any and all prior agreements between you
     and the Company, with the exception of the Proprietary Information and
     Inventions Agreement and any agreements relating to your Option.
 11. You agree that if any provision of this Agreement is found to be invalid,
     the remainder of this Agreement shall not be affected by such a
     determination.
 12. This Agreement shall be construed and interpreted in accordance with the
     laws of the State of California.
 13. You agree that this is the entire agreement regarding the subject matter
     hereof and supercedes all previous negotiations, agreements and
     understandings.
 14. You and the Company agree that this Agreement may be executed in
     counterparts, each of which shall be deemed an original, but all of which
     together shall constitute one and the same instrument.
 15. You and the Company agree that a facsimile signature on the Agreement shall
     be as effective as an original signature.

Please indicate your agreement with the above terms by signing below.

Sincerely,

/S/ Jo-Ann Byrne

My signature below signifies my agreement with the above terms. Furthermore, I
acknowledge that I have read and understand the foregoing letter and that I sign
this release of all claims voluntarily, with full appreciation that I am forever
foreclosed from pursuing any of the rights I have waived.

Signed: /S/ Ike Udechuku

Ike Udechuku

Dated: _____________________

 

Align Technology, Inc. agrees to the foregoing.

Align Technology, Inc.

By: ______/s/ Jo-Ann Byrne______________________

Dated: ________________