Aimed to evaluate the lovastatin action on Schistosoma mansoni oviposition, infected mice with 100 plus minus 10 cercariae of the LE strain were used. Thirty days after infection the animals were treated with 100, 200 and 400mg/kg of lovastatin, per os, during five consecutive days and then sacrificed 7, 15, 30 or 60 days after treatment. We analyzed: distribution of worms in mesenteries and liver; mortality of worms in the liver; alteration of the oogram; eggs counting in the jejunum and liver; presence of intrauterine eggs and morphology of the worms from the treated and control groups (infected and not treated animals). Significant statistical differences were found between treated and control groups when the presence of intrauterine eggs was considered and also, alteration on the oogram, eggs at different stages of development in jejunum, liver and in the body length of males and females. The morphological study of the worms showed that the degenerative modifications occurred, mainly in the reproductive system, with reduction and alteration of the viteline follicles and the ovary of the females. Also modifications in the males testicles were observed. The results suggest that the drug under study reduces, considerably, the female S. mansoni, oviposition increases the worms' size, leads to alteration in the reproductive system of males and females. It also may induce death of a significant part of the worm populations at the dose of 400mg/kg.