This study investigated the effects of androstenedione and follicle-stimulating hormone (FSH) on the viability and growth of caprine preantral follicles. Ovarian tissues were cultured for 1 or 7 days in Minimum Essential Medium (MEM+ ) containing androstenedione (0, 1, 10, 50, or 100 ng/ml), FSH (50 ng/ml), or a combination of these two hormones. Cultured and noncultured control tissues were processed for histological and fluorescence analysis. In comparison with noncultured control, a significant reduction was noted in the percentage of normal follicles in all treatments after 1 and 7 days of culture (except treatment with 1 ng/ml of androstenedione for 1 day). As the culture period progressed from 1 to 7 days, treatments with 10 ng/ml of androstenedione + FSH or 50 ng/ml of androstenedione alone maintained the percentage of normal follicles. After 1 day, treatments with 10, 50, or 100 ng/ml of androstenedione + FSH, or with 50 ng/ml of androstenedione alone had more developing follicles than fresh control tissue. When comparing the culture periods, treatments with 1, 10 or 100 ng/ml of androstenedione alone, or FSH alone, or FSH with 1 ng/ml of androstenedione, showed an increase in the percentage of developing follicles. After 1 and 7 days, there were no differences in oocyte and follicular diameter among the treated samples and non-cultured control or MEM+ cultured tissue. Fluorescence analysis demonstrated that only fragments cultured in 50 or 100 ng/ml of androstenedione + FSH had viable preantral follicles similar to those observed in MEM+ alone. In conclusion, androstenedione at 50 or 100 ng/ml, either associated with FSH or at 50 ng/ml alone, plays an important role in the maintenance of caprine preantral follicle viability and activation after only a short in vitro culture period. In addition, after 7 days MEM+ alone was efficient in the maintenance of viability and in follicular activation, showing the importance of basic medium composition.