OBJECTIVES: Testosterone is mainly used as androgen replacement therapy. The purpose of this study was to describe utilization trends of various testosterone formulations in a real life setting, using the RAMQ database.  METHODS: Male patients covered by the Quebec provincial drug reimbursement program (RAMQ) who had used at least one formulation of testosterone in the period from June 1, 2003 to March 31, 2011 were selected. Characteristics of the treatments were analyzed, including switches from one formulation to another. A 1:1 control group matched for age of patients not using any formulation of testosterone was created and incidence of co-morbidities in patients in the study group was compared to the control group.  RESULTS: Among a random sample of 125,000 patients covered by the drug plan, 723 males used at least one formulation of testosterone (0.57%). The average age was 57.2 years (SD=14.4). A total of 7 different formulations of testosterone were used by these patients. The most frequent formulations used during the study period were Andriol® (48.4%) and Androgel® (41.4%).  Testosterone formulations were mainly prescribed by GPs (73%), endocrinologists (11.9%) and urologists (7.5%). About 32% of patients used more than one formulation during the study period. Among patients who switched from one formulation to another, switching to Androgel was the most frequent trend. Average treatment persistence varied from 147 days with Testim® to 674 days with Androgel. Prevalence of many co-morbidities was significantly higher amongst these patients compared to the control group. Co-morbidities included mental disorders (63.2%), hyperlipidemia (63.8%), hypertension (51.2%), articulation pain (32.1%) back pain (31.4%), HIV (6.2%) and migraine (6.6%) CONCLUSIONS: Patients on androgen replacement therapy have significantly more co-morbidities than controls. A significant proportion of patients will switch to a different formulation of testosterone over time, Androgel being the most frequent choice.