this study was conducted in order to verify the effect of different concentrations of bmp-7 in the in vitro survival and development of caprine preantral follicles. fragments of caprine ovarian cortical tissue were cultured for 1 or 7 days in minimum essential medium (mem+) supplemented with different concentrations of bmp-7 (1, 10, 50 or 100ng/ml). non-cultured fragments or those cultured for 1 or 7 days were processed for classical histology and transmission electron microscopy (tem). parameters such as follicular survival, activation and growth were evaluated. the results showed that, after 1 or 7 days of culture, the percentage of morphologically normal follicles was significantly reduced in all treatments when compared with fresh control, except at 1ng/ml of bmp-7 for 1 day. in addition, the concentration of 10ng/ml of bmp-7 significantly increases follicular diameter from day 1 to 7 of culture. there was no influence of the other concentrations of bmp-7 regarding to the follicular and oocyte diameter. ultrastructure studies confirmed follicular integrity after 7 days of culture in 1ng/ml bmp-7. in conclusion, small concentrations of bmp-7 can improve the survival and growth of caprine preantral follicles during in vitro culture.