Length-weight relationship was studied in Rainbow trout (Oncorhynchus mykiss) collected from Kokernag and Verinag(Jammu and Kashmir). A total of 70samples of rainbow trout ranging from length 20 to 35.3 cm, weight ranging from 175 to 810 and breadth from 4.8 to 9.4. The length-weight relationships shows the b value were 3.39. During the present study, the length weight relationships of Rainbow trout increases proportionally with increase in length. The condition factor was found to be 1.83.