1 EXHIBIT 16.1 September 9, 1999 Securities and Exchange Commission 450 Fifth Street, N.W. Washington, DC 20549 Gentlemen: We have read "Change in Accountants" on page 81 of the Registration Statement (Form S-1) of Quintus Corporation, and are in agreement with the statements contained therein. We have no basis to agree or disagree with other statements of the registrant contained therein. /s/ ERNST & YOUNG LLP