Sheep are considered less susceptible to leptospirosis than other livestock species, and reports of reproductive problems are scarce in scientific literature. Thus, our objective was to report an epidemic outbreak of leptospirosis in a flock in southern Brazil, causing economic impact represented by several numbers of abortions and barren ewes. From a flock of 602 sheep, 79 ewes had problems during gestational period. Blood samples were collected from 25 of these 79 ewes, 10 with confirmed abortion, 10 barren, and 5 ewes that delivered normally. Serum was separated and subjected to serological evaluation. Samples were examined for Leptospira antibodies by the microscopic agglutination test (MAT) as well as subjected to a differential diagnosis for toxoplasmosis and neosporosis. From the 25 sera analyzed, 19 (76 %) were positive while 6 (24 %) were negative, with single serovar response observed in 12/19 (63.16 %) while mixed serovar positivity was observed in 7/19 (36.84 %). Regarding to serovar prevalence, Hardjo titration was observed in 15/19 (78.95 %) and Wolffi in 9/19 (47.37 %). No samples were positive for toxoplasmosis or neosporosis. Therefore, based on the serological results reached by MAT, it is possible to strongly suggest the participation of Leptospira spp., especially serovars Hardjo and Wolffi, in the reproductive flaws reported in this short communication.