ABSTRACT OBJECTIVE To identify and analyze the prevalence, trend, and factors associated with episiotomy in Rio Grande, in the state of Rio Grande do Sul, Southern Brazil. METHODS A single, standardized questionnaire was applied to all pregnant women, residents in the municipality of Rio Grande, who had children in local hospitals between January 1 and December 12 of the years 2007, 2010, 2013, 2016 e 2019. Demographic and socioeconomic characteristics were investigated, as well as the assistance received during pregnancy and delivery. Chi-square test was used to compare proportions and Poisson regression with robust variance adjustment was used for multivariable analysis. Prevalence ratio (PR) was used as effect measure. RESULTS Among the 12,645 births that occurred in the five years, 5,714 (45.2%) were vaginal delivery. Of these mothers, 2,930 (51.3%; 95%CI: 50.0%-52.6%) underwent episiotomy. Over this period, the episiotomy rate decreased from 70.9% (68.4-73.5) in 2007 to 19.4% (17.1-21.7) in 2019. Adjusted analysis showed a high PR of episiotomy occurrence among women who were young (PR = 2.23; 95%CI: 1.89-2.63), had higher education (PR = 1.21; 95%Cl: 1.03-1.42), had a higher family income (PR = 1.25; 95%CI: 1.10-1.41), were primiparous (PR = 3.41; 95%CI: 2.95-3.95), had prenatal care in the private sector (PR = 1.25; 95%CI: 1.07-1.46), had oxytocin-induced labor (PR = 1.18; 95%CI:1.09-1.27), underwent forceps (PR = 1.32; 95%CI: 1.16-1.50), and whose newborn weighed 4,000 g or more (PR = 1.43; 95%CI: 1.14-1.80). CONCLUSION Although the prevalence of episiotomy fell sharply within the studied period, its occurrence is more likely among women at lower risk of birth complications.