The goal of this project was to provide empiric evidence about the benefit to US veterans and the VA of capturing data from a citywide clinical informatics network (INPC) to assess care received outside the VA. We identified 468 veterans diagnosed with colorectal cancer from 2000-2007 in the Indianapolis VA cancer registry. Electronic VA healthcare data were linked with electronic health records from the regional health information organization (RHIO) INPC; 341 matches were found. Both the VA and INPC systems were queried regarding receipt of surveillance tests. The proportion with additional data from INPC varied by test: colonoscopy (3%), CT scan/abdomen (13%), CT scan/chest (79%), carcinoembryonic antigen test (8%), and other laboratory tests (25%-53%). An incremental benefit of linking VA and INPC data was present and may increase when expanded beyond patients with a single condition. New, important information about care outside the VA is obtained through RHIO data linkage.