The study evaluated effect of Sex on serum biochemical parameters and Correlation with body weight of Japanese quails. A total of 400 birds (200 birds per sex) were reared in a Completely Randomized Design under standard management practices for 7 weeks with feed and water given ad libitum. Sex were considered treatments. Weekly body weight (BW) was measured. The three authors have declared that, “principle of laboratory animal care” (NIH publication 85 - 23 revised 1985) were followed as well as the University law. All the experiment have been examined and approved by the University law.100 birds per sex were randomly selected and blood samples were collected for serum biochemical parameters: blood Glucose (GLU), Total Cholesterol (CHOL), Triglycerides (TG), Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Alkaline Phosphatase (ALP), Total Protein (TP), Albumin (ALB)and globulin (GLB). The results indicated that sex significantly (P < 0.05) influenced all the serum biochemical parameters of Japanese quail measured in this study at week 7. All data collected were analyzed with GLM of SAS ver. 9.2 and means were separated. Females of Japanese quail had the higher least square means in the serum biochemical parameters of Japanese quails than the Male counterparts. Females showed higher means in TP, ALB, GLB, TG, CHOL, AS, ALT and GLU significantly (P<0.05) higher than males with for the same parameters, respectively. However, males showed higher significant (P<0.05) difference in ALP than females measured. Correlation between BW and serum biochemical parameters for male quails ranged from -15% to 15% (low trend) while that of Female counterparts was -73% to 73% (low to high trend). In conclusion, female quails had higher values in TP, ALB, GLB, TG, CHOL, AST, ALT and GLU than the Males counterparts’ exception of ALP. Hence, female quails were considered fit for studying quails’ health status as early clinical signs will be observed for quick responds to arrest the situation that will lead to disease outbreak and a breeding program will be established for quails. Body weight of female quails is a good selection tool to predict serum biochemical parameters of quails. The correlation coefficient between body weight and serum biochemical parameters was high and significant in favor of female Japanese quails.