The length, weight and sex distribution of turbot caught by bottom turbot gill nets were investigated in relation with seasons in the Sinop region. The size ranges were 23.9-69 cm and 31.8-81 cm for male and female turbot, respectively. Mean total length and weight were 50.37 ± 0.42 cm and 2483.2 ± 74.7 g for females, 45.93 ± 0.26 cm and 1711.2 ± 31.2 g for males, and 47.79 ± 0.24 cm and 2034.6 ± 38.5 g for all individuals. Significant differences were found both in length and weight values of turbot between seasons. The highest mean length and weight values were 49.56 ± 0.35 cm and 2286.5 ± 59.6 g in the spring, respectively. The length frequencies of turbot differed significantly between spring and other seasons (P < 0.001). Significant differences were found for sex ratios of turbot in spring. The length-weight relationship was estimated as W = 0.0074 L322. © TÜBİTAK.