Adults infected with HIV live longer when they receive regular medical care, yet many adults are not retained in care. Providers measure retention in order to evaluate interventions to improve retention and quality of HIV care. However, multiple measures for retention exist. This study compares two methods of operationalizing retention and evaluates the contribution of individual characteristics on the likelihood of retention. A chart review was performed for a random sample of 212 active clients of an urban HIV primary care clinic. Data on clinic utilization, sex, age, race, mental illness, substance use, AIDS diagnosis, language, and housing were collected for each participant. Clinic utilization data were used to classify participants for retention status and to score them by frequency of visits. Binary logistic regression analysis was compared with ordinal logistic regression analysis, using distinct retention measures as outcome variables. In the binary model, those with a history of substance use were about half as likely to be retained (OR 0.52, 95% CI 0.29-0.94) and those with an AIDS diagnosis were more than twice as likely to be retained (OR 2.18, 95% CI 1.17-4.09). These characteristics were significant predictors in the ordinal model, with the additional finding that those reporting English as a primary language were less likely to have higher retention scores (OR 0.40, 95% CI 0.19-0.84). An ordinal score for retention can identify unexpected predictors, but a dichotomous measure of retention may be easier to use and interpret for providers involved in retention-related quality improvement activities.