Serum biochemical parameters are important aspects in the management of endangered species. The values of these parameters can be used for confirming the maturity and for monitoring any changes in the quality of waters and related soils. The aim of present study was to investigate some of blood serum biochemical parameters in immature females and males of Argyrosomus hololepidotus. Blood samples were collected from twenty captured fish from coastal waters of Chabahar (Ramin waterfront). Serum levels of glucose, blood urea nitrogen (BUN), cholesterol (CHO), triglyceride, bilirubin, total protein, albumin, phosphorus (P), sodium (Na), potassium (K), calcium (Ca) and alkaline phosphatase (ALP) were determined as Mean±SD in immature males and females. The levels of different biochemical parameters in males and females were respectively as follows; Na (239.50±17.06, 257.80±20.80), K (3.87±0.98, 1.94±0.49), P (2.73±0.39, 2.79±0.53), Ca (2.89±0.47, 1.56±0.32) (mmol/l), glucose (71±10.33, 24.04±2.50), bilirubin (0.46±0.11, 0.24±0.05), ALP (68.30±124.17, 244.50±68.98) (Iu/l), BUN (1.94±0.50, 0.63±0.29), triglyceride (94.70±9.56, 32.85±7.56), CHO (13.02±2.69, 4.94±3.29) (mg/dl), total protein (1.65±0.51, 3.15±0.86) and albumin (0.44±0.16, 0.12±0.04) (g/dl). The results showed that the serum levels of Na and total protein in females were significantly higher than males and there were significant differences in all of the serum values (except P) between males and females (P<0.05).It can be concluded that the values of blood biochemical parameters may be affected by sex of fish.