The duration of individual stages of meiosis and spermiogenesis in Anabas testudineus (Bloch) was estimated autoradiographically by using H₃-TdR. The leptotene, zygotene and pachytene last for 0.33±0.08, 0.20 and 1.80±0.10 days respectively whereas the duration of diplotene, diakinesis and metaphase I is comparatively longer and last for about 1.30±0.20 days. The spermiogenesis is completed within 6.60±0.40 days whereas the total duration of meiosis and spermiogenesis is about 10.50 days.