The purposes of this study were to estimate the population of caprine preantral follicles, and to evaluate quantitatively and qualitatively the efficiency of a specific mechanical method for the isolation of preantral follicles from mixed breed goats at different reproductive stages. On average, 37,646+/-4277 preantral follicles were present in goat ovaries, and 13,631+/-2399 preantral follicles were obtained after isolation. The number of preantral follicles isolated or in situ was not significantly affected by the reproductive stage. The mean recovery rate per ovary ([number of isolated follicles/number of in situ follicles] x 100) of isolated follicles was 36.2%. The distribution of follicles in situ was 67.8% primordial, 25.8% primary and 6.4% secondary; the respective distribution after isolation was 93.8%, 5.2% and 1.0%. In this study, many polyovular follicles were also observed, mainly in prepubertal goat ovaries. Histological analysis showed that few preantral follicles were atretic in situ (4.83%+/-0.35) or after the isolation procedure (4.67%+/-0.65) in the three reproductive stages. The percentage of atretic follicles was not affected either by the mechanical method or by the reproductive stage. It is concluded that a large number of preantral follicles can be successfully isolated mechanically, with a high recovery rate and a low rate of follicular atresia, irrespective of the reproductive stage of the caprine female.