This study compared in-house Grateful Med database use and searching success rates for four-month periods at four sites of the Library of the Health Sciences of the University of Illinois at Chicago. Data were collected from Grateful Med workstation uselogs and analyzed. Database use patterns and searching success rates were fairly consistent across the four sites. Though MEDLINE was available in other formats and use in these other formats remained high, 65.48% of all Grateful Med searching was done by using MEDLINE, and an additional 21.34% was done by using the MEDLINE Backfiles. In-house use patterns were similar to the overall use pattern for the University of Illinois, with the exception of MEDLINE Backfiles. Overall, 54.30% of searches were successful.