Exhibit 23.3 CONSENT OF PricewaterhouseCoopers LLP INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of Nuvelo, Inc. of our report dated June 2, 2003, relating to the financial statements of Variagenics, Inc., which report appears in the Current Report on Form 8-K/A of Nuvelo, Inc. dated July 3, 2003 and which Form 8-K/A is incorporated by reference in this Registration Statement Form S-8 of Nuvelo, Inc. /s/ PricewaterhouseCoopers LLP Boston, Massachusetts September 3, 2003