Abstract: The aim of this study is to investigate of steroid hormones of male Siberian sturgeon in different seasons. For this, blood sampling was taken seasonally from 11 male Siberian sturgeons (7 years old) and then steroid hormones including testosterone and 11-keto testosterone were analyzed by using ELISA. The results showed that testosterone had no significant differences during all the seasons (p>0.05) and the maximum level was in autumn. But 11ketotestesterone had significant differences between winter with other seasons (p<0.05). The min and max level of 11ketotestesterone was in autumn and winter, respectively. 11-keto testosterone hormone levels based on sexual maturation stages showed significant difference between stages III and IV with stage II (p<0.05). Also, there was significant differences between stage II with others in testosterone levels (p<0.05).