In the present studies, Length-weight relationship of Labeo dero (Family: Cyprinidae) was studied on about 300 specimens (ranging from 3.1cm to 27.5 cm Total length and 0.43gm to 200.10 gm of Body Weight). The value of correlation coefficient indicated a highly significant correlation between length and weight in all the age groups. It was 0.978 in age group 0⁺, 0.999 in age group 1⁺, 0.995 in age group 2⁺, 0.983 in age group 3+ and 0.995 in pooled data of all age groups. The parabolic equation obtained were W= 0.11480L^2.756, W= 0.00575L^3.149, W= 0.00395L^3.319 and W=0.04920L^2.521 in 0⁺, 1⁺, 2⁺, 3⁺ age groups respectively. The condition factor (K) also varied in different age groups was found to be decreasing with advancing age viz. 1.2268, 1.1015, 1.1008, 1.0343 in 0⁺, 1⁺, 2⁺ and 3⁺ age groups respectively.