The present work aimed to study some aspect of the reproductive biology of the P. javanicus with emphasis on histopathology abnormalities of gonads and intersex problems. Fish samples of Puntius javanicus (local name:tawes) were collected from Mas River on the Surabaya downtown whereas highly pollution. Fishes were identified for morphological abnormality and gonad organs were evaluated. Histological preparation was done to observe the gonad condition. This report reveals that 20% male P. javanicus were found to be feminized on July 19, 2012 collection from that river. Some histological samples indicated the presence of testis-ova in fish gonad, which indicated the occurrence of intersex of this species. The above finding suggests that greater attention needs to be given to xenobiotic pollutants and endocrine disrupting chemicals problems.