This study was taken to examine correlationships between ehdocrine changes such as estradiol-17$eta$, progesterone, T4 and T3 and serum components concentrations of female Oreochromis niloticus living in 0$ extperthousand$, 10$ extperthousand$, 20$ extperthousand$, and 30$ extperthousand$ salt concentrations, respectively. The results obtained in these experiments were summarized as follows. Correlation coefficients of serum albumin and thyroxine were ＋0.907 and ＋0.611 in 10$ extperthousand$ and 20$ extperthousand$, respectively. In 30$ extperthousand$ salinity, serum BUN and other 3 kinds of hormones showed all negative correlation coefficients. Correlation coefficients of serum estradiol-17$eta$ with calcium and cholesterol in 20$eta$ were ＋0.624, ＋0.733, respectively. Correlation coefficient between serum triglycerides and thyroxine in 30$eta$ was ＋0.989.