Objective: To assess gender distribution in polymyositis (PM) and its infl uence on disease, regarding clinical and laboratory manifestations, outcome and comorbidities. Methods: Retrospective single-center cohort study assessing 75 consecutive patients with PM ) from 1990 to 2010. Complementary tests were related to early diagnosis of PM. Results: The study assessed 52 women and 23 men (ratio 2.3:1), most of whom white (84.0%), with a mean age of 42.7 ± 13.7 years (16 to 67 years), and mean disease duration of 6.9 ± 5.5 years (0 to 20 years). Approximately 50% experienced disease relapse during follow-up. Nevertheless, two thirds were in remission at the end of this study, with 4.0% of deaths. There was no difference between genders regarding demographic, clinical and laboratory characteristics, clinical outcome and the drug therapy instituted. Regarding comorbidities, there was a high prevalence of hypertension (38.7%) and diabetes mellitus (17.3%), equally distributed between genders. There was also a high prevalence of depression and fi bromyalgia, which were only observed among females. Conclusions: The prevalence of PM was higher among women than among men (2.3:1). Because the prevalence of comorbidities was high in the case series studied, it is worth emphasizing the need for their control to provide better quality of life for patients with PM.