The objective of this study was to examine the number and characteristics of National Health Service Corps (NHSC) alumni who currently practice with an underserved population. The study design was a cross-sectional survey mailed in 1998 to a sample of 2,160 alumni. The response rate was 58.9 percent; overall, 52.5 percent of respondents reported currently working with the underserved. In bivariate analyses, retention in practice with the underserved was associated with several clinician and service experience variables. In a logistic regression model, higher initial desire to work with the underserved, older age, job satisfaction, and higher salary were associated with current service. The authors conclude that more than half of the NHSC alumni responding to the survey reported working with an underserved population in 1998. Associations between clinician and service experience characteristics and retention in practice with the underserved can inform policy and research to improve retention.