Studies on seasonal variations in aquatic, aerial and total oxygen uptake in a fresh water facultative air breathig fish, Clarias batrachus (Linn. ) were made for a period of twelve months. In this fish aquatic, aerial and total 0, uptake ranged respectively between 4 1. 8-61. 2; 6. 2-30. 8 and 49. 0-91. 0 cc/kg/h. The percent 0, uptake through aerial route were lowest (12.157%) in January and highest (33.846%) in June. The aquatic/aerial ratio was lowest (1.945) in June and highest (7.226) in January. The reason for such variations have been discussed in this paper.