Exhibit 16 August 31, 2000 Securities and Exchange Commission VIA FACSIMILE Mail Stop 11-3 (202) 942-9656 450 5th Street, N.W. & HAND DELIVERY Washington, D.C. 20549 Dear Sirs/Mesdames: We have read and agree with the comments in Item 4 of Form 8-K of Southwest Bancorp, Inc. dated August 31, 2000. Yours truly, /s/ Deloitte & Touche LLP