Maintaining yield potential or reducing yield losses is very important for soybean [ Glycine max ( L.) Merr.] double cropping to be profitable. Our objectives were to study the effects of cultivar maturity on yield, yield components and to determine adaptation and yielding potential of 18 soybean cultivars ( six cultivars in each of the maturity groups II, III and IV) in the eastern Mediterranean region of Turkey in 2000 and 2001. The experimental design was randomized complete block with three replications. Effects of maturity group ( MG) on seed yield, yield components, and key phenological stages were significant. Cultivars in MG IV had significantly higher seed yield, plant height, lowest pod height and number of nodes/ plant than cultivars in MG II and III. Among cultivars, the highest seed yield was obtained from KS4895 ( MG IV) with 3.75 t/ha and the lowest was obtained from Dwight ( MG II) with 1.18 t/ha. Except for the number of seeds/pod, all of the measured yield components and key phenological stages were significantly and positively correlated with seed yield. Based on the path analysis of the combined data, it was found that the number of seed/m(2), the period from VE to R1 and from R1 to R7 had greatest positive direct effect on seed yield. The results of the current study showed that cultivars in MG IV were best adapted and best suited for a wheat-soybean double cropping system in the eastern Mediterrenean region of Turkey.