This is the first study providing information on some morphometric parameters for Pontastacus leptodactylus from Sapanca Lake (Sakarya), Türkiye. This study was conducted from June - 2016 to October - 2017 and a total of 264 crayfish were caught, being 146 females and 118 males. The results revealed that the average total length for the population was 91.89±15.68 mm (TL±SD) (94.75±15.91 mm for females, 88.36±14.72 mm for males), and the average total weight for the total population was 27.27±16.84 g (TW±SD) (29.02±17.54 g for females, 25.09±15.74g for males). The sex ratio was computed as 1.24:1 (female to male). A strong positive statistical relationship was determined between the total length and total weight of females, males, and both sexes (r2: 0.90 – 0.95). This statistically strong relationship was also valid between other body parts, such as carapace length, width, and weight. The regression analyses for total length-total weight relationships also revealed that the whole population exhibited positive allometric growth (b=3.186) regardless of sex, and the condition factor for all sex groups was computed to be over 3 (K=3.23±0.60 SE).