Abstract: The age and the growth parameters of the roach (Rutilus rutilus L., 1758) caught in Sapanca Lake were investigated monthly between October 2000 and September 2001. The age values of the 398 roach caught were between 1 and 9 and the majority of the fish consisted of individuals of the 5 and 6 age group. The difference between the average lengths with respect to sex was significant in 1, 2, 5 and 8 age groups (p<0.05). The von-Bertalanffy equation was determined with Lt = 31.87 (1-e0.195(t+0.034)); Wt = 380.91 (1-e0.195(t+0.034))3 for males and Lt = 47.19(1-e0.109 (t+0.056); Wt = 1256.93 (1-e0.109(t+0.056))3 for females. The relationships between length and weight were found highly significant (r = 0.99). The differences of mean length, weight and condition factors between females and males in the same length groups were compared. The length-weight correlation was found to be W = 0.014 L2.933 for male and W = 0.013 L2.972 for female. The mean values of condition factors (K) of females and males were determined as 1.241±0.02 and 1.221±0.03, respectively.