Failure to follow up outpatient test results is a potential patient safety concern; however, data about how house-staff physicians follow up on tests are sparse. The authors sought to assess internal medicine house-staff practices and perceptions regarding the follow-up of outpatient tests and identified barriers to timely follow-up. Seventy-five of 111 eligible house staff at a large urban teaching hospital (68%) completed the survey. Seventy-four percent reported they were sometimes unable to follow up on test results, 78% were at least somewhat worried about inadequate follow-up, and 46% stated that they have seen a patient's medical condition worsen due to a delay in test result follow-up at least a few times a year. Barriers to timely follow-up included lack of a reminder system (40%), difficulty accessing results (24%), too many competing demands on time (27%), and uncertainty about who should follow up on results (16%).