The relationships among 15 morphometric measurements in 219 aliquots of European seabass (Dicentrarchus labrax) were examined with respect to sexual dimorphism. The ratio of females to males was determined as 1:5.1 and gonadosomatic indices (%) were found for males (2.13 +/- 0.86) and females (3.63 +/- 1.18). There were 4 morphometric characteristics that differed between genders: ventral margin of cleithrum (VMC), postanal fin length (post-AFL), postdorsal fin length (post-DFL), and preanal fin length (pre-AFL). Although there were significant differences between morphometric characteristics (post-AFL, post-DFL, pre-AFL) and total length, no significant differences were found in the VMC. These average ratios were determined as pre-AFL to TL 0.61 female, 0.71 male; post-AFL to TL 0.72 female, 0.84 male; post-DFL to TL 0.68 female, 0.81 male, respectively. The aim of this study was to investigate if sexual differences could affect external morphology in cultured seabass and, additionally, to determine sexual dimorphism related to morphological differences during the maturation and spawning seasons in this species.