In this study 225 and 252 specimens of Capoeta trutta were captured monthly from Alvand and Gamasiab Rivers during August 2008 and July 2009, respectively. The following measures were estimated for the fishes of the two rivers: Age range of fishes in Alvand and Gamasiab Rivers were 1-6 and 1-5, respectively. Sex ratio (M:F) in population of  Capoeta trutta in Alvand and Gamasiab Rivers were 1.27 : 1 and 1.96 : 1, respectively with male fishes as the dominant gender in both rivers. Furthermore, range of total length in Alvand and Gamasiab Rivers were 171-426 and 166- 313 mm, respectively.  Range of body weight   in Alvand and Gamasiab Rivers were 58- 798 and 50- 352 gr, respectively. Also, length- weight relationship in male and female fishes in Gamasiab River were y=0.00007x ^2.246 and y= e^-0.5 x^2.72, and in male and females of Alvand River were were y=5e^-0.5 x^2.741 and y=3e^-0.5 x^2.81,  respectively. The (b) value in length-weight relationship showed that the growth model of C.trutta was negative alometric in both rivers. Fishes in Alvand River can reach higher length and weight in comparison with Gamasib River which shows a more stable ecological conditions and food abundance in this river