To evaluate the prevalence of diabetes mellitus in the surgical population of the University of Puerto Rico (UPR)-affiliated hospitals. We examined all the surgical cases that were entered into the Surgical Database from April 1, 2014 through September 30, 2014. This database collects patient and procedural information from different surgical services of various UPR-affiliated hospitals (the University District Hospital, the University Pediatric Hospital, the UPR Carolina Hospital, the Dr. Isaac Gonzalez Oncologic Hospital, the PR Cardiovascular Center [thoracic service], the Pavia Hospital [colorectal service], and the Auxilio Mutuo Hospital [colorectal and oncological services]). The prevalence of diabetes mellitus (types 1 and 2 combined) was estimated, and the nondiabetic and diabetic groups were compared. The difference between groups was evaluated using a Chi2 test, Student's t-test, or ANOVA, whichever was appropriate, with a p-value of less than 0.05 being considered significant. Information from 2,603 surgical patients was available. The mean age of the group was 49 (±23) years. The gender distribution indicated that 56% were women and 44% were men. Diabetes was present in 21% of the surgical population, increasing to 40% in patients aged 65 and over. The surgical procedures most frequently required by diabetic patients were in the categories of general surgery (36%), colorectal surgery (22%), vascular surgery (16%) and oncologic surgery (14%). Complications (5%, diabetic group vs. 2%, nondiabetic group; p < 0.05) and postoperative mortality (2%, diabetic group vs. 0.2%, nondiabetic group; p < 0.05) were significantly higher in the diabetic group than in the nondiabetic group. Our surgical population has a high prevalence of diabetes, and these diabetic patients showed higher complication and mortality rates from surgery than did the non-diabetic patients. Surgeons must consider the specific needs of these diabetic patients in order to provide optimal care.