During last ten years, the book “Fishes of Eastern Uttar Pradesh” has been well received by the teachers, research scholars, students and the field workers of Ichthyology in India and abroad. Looking to the interest of the Ichthyologis, it was felt that the book should be revised and enlarged to accommodate the fishes of some more regions in the larger interest of its users. Name of the book has now been changed to “Fishes of U.P. and Bihar”. Contents : List of Fishes, Explanation of terms & abbreviations used, Material and Mehtod, Class—Teleostomi, Order—Clupeiformes, Order—Cypriniformes, Order—Beloniformes, Order—Cyprinodontiformes, Order—Mugiliformes, Ophiocephaliformes, Order—Symbranchiformes, Order—Perciformes, Order—Mastacembeleformes, Order—Tetrodontiformes, Literature cited, Index.