OBJECTIVE. The purpose of this study is to assess whether providing a formal report for outside imaging reduces repeat imaging. MATERIALS AND METHODS. From January 1, 2006, through December 31, 2011, patients transferred with an abdominal CT from another ("outside") institution that was imported to our institution's PACS within 60 days of the original CT were considered. Repeat imaging was defined as when an abdominal CT performed at another institution was followed by the same study at our institution in the 14 days after import to PACS. The rate of repeat imaging was compared between patients whose outside imaging did and did not receive a formal report from our radiologists. RESULTS. Consecutive patients (n = 10,330) who imported an outside abdominal CT to our PACS were considered. Thirty-six percent (3719/10,330) received a formal report. These patients were 32% less likely than the other patients to undergo repeat imaging (9.4% [350/3719] vs 14% [919/6611]; p < 0.001). The odds of repeat imaging were statistically significantly lower for patients who received a formal report after adjusting for potential confounding variables, including the age of the outside imaging study and the referring specialty (multivariate odds ratio, 0.53; 95% CI, 0.47-0.61; p < 0.001). CONCLUSION. Patients who received a formal report for their outside abdominal CT examinations were less likely to have repeat imaging. Institutions, payers, and policy makers should consider providing and supporting formal reports for outside imaging.