Objective: The objectives of the study were to assess (1) if serum levels of testosterone differ between men with and those without ST-elevation myocardial infarction, and (2) to determine the association of testosterone with the outcome of ST-elevation myocardial infarction (STEMI). Methodology: This was hospital based case control study, conducted at Coronary Care Unit of Teaching Hospital, Karapitiya, Galle, Sri Lanka from January 2010 to December 2011. Two hundred and six males (103 patients with STEMI and 103 controls without a history of CAD) were studied. They were followed up for one year for the occurrence of clinically significant adverse cardiovascular events. Serum total testosterone, lipids and plasma glucose were estimated. Results: The basal serum total testosterone in patients was significantly lower compared to controls (11.47 +/- 3.3 vs. 18.15 +/- 7.2 nmol/L, P = 0.001). The results showed that total testosterone (P = 0.001; OR = 0.75; 95 % CI = 0.66 - 0.85) was a significant independent predictor of STEMI and it was a significant independent predictors of in-hospital complications (P = 0.003, OR = 1.68, 95 % CI = 1.2 - 2.36). Conclusion: Men with STEMI have significantly lower basal serum total testosterone compared to controls. Low testosterone is a risk factor of STEMI. Testosterone was independently related to the development of in-hospital complications of STEMI.