ABSTRACT:Objective: To examine the variation in the rates of psychiatric hospitalization and the mean hospital stay time in the public health system in the state of Rio Grande do Sul, in the south of Brazil, from 2000 to 2011. Methods: This was an ecological study. Data were collected from DATASUS. The rates were obtained from diagnosis of admissions due to psychoactive substance use and to other causes, stratified by the gender of the patients. The data were analyzed using Poisson regression and Spearman correlation coefficient. Results: Increasing hospitalization rates were observed for women with disorders due to substance use (p < 0.001) and other causes (p < 0.001), and among men with disorders due to the use of alcohol or other drugs (p < 0.001). This elevation of the rates remained statistically significant and inversely correlated to the length of hospital stay (p < 0.001). Discussion: In a period of expansion of the local care networks for mental health, an increase in the occupancy of psychiatric beds in the state was noticed, with shorter length of stay and greater diversity of gender and causes of hospitalization.