This study was investigated morphometric aspects, reproductive biology (gonadosomatik in-dex), of cuttlefish Sepia officinalis (L.) from September 2002 to September 2003. Samples collected in 22 trawl surveys from commercial vessels on Karata? coasts. The trawl surveys carried out at depths from 20 to 120 m. It investigated that total 217 females, 399 males, and 289 indeterminate individuals. The mean mantle lengths of males, females, and indeterminate individuals were 98.36 ±0.84 mm, 105.88 ±1.19 mm, and 61.89 ±1.02 mm respectively. The relationships between mantle length and the total length are linear. The MB: W relationships are isometric. The population of mature males were dominant to females (sex ratio=0,54:1). Female individuals with ripe gonads (IV,V) were dominant from January until April, and fe-males with pre-mature gonads (I) showed in June. It showed that spawned occurred between April and September in off coastal area of Karata?.