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This study aimed to investigate some of serum electrolytes and white blood cells of wild stellate sturgeon (A. stellatus) which have been caught off the coast of Mazandaran by trawl methods during 5 maritime patrol from 2009 to 2010.  Initially, 2 ml blood samples of 30 wild juvenile stellate sturgeon were extracted for spread of differential blood count, and serum electrolyte to test factors such as calcium, magnesium, cholesterol, albumin and total protein were separated. To conduct statistical evaluation and comparison, fishes were divided into two weight groups of 10 – 30 gr and 31 – 50 gr. Result of differential count  showed that the most and the least abundance of leukocytes were belonged to lymphocyte and monocyte in both two groups, respectively. Serum electrolytes results showed that mean levels of cholesterol, calcium, magnesium, albumin and total protein in A. stellatus at group 1 were 28.1 ± 10.6 mg/dl; 24.7 ± 1.6 mg/dl; 26.7 ± 1.8 mEq/l; 1.4 ± 0.3 g/dl and 2.2 ± 0.3 g/dl, respectively. At group 2, these parameters levels were 71.14 ± 2.4 mg/dL, 20.6 ± 0.8 mg/dL, 17.4 ± 3.4 mEq/L, 1.6 ± 0.2 g/dl and 2.3 ± 0.2 g/dl, respectively. No significant difference was observed between the white cells counts of the two groups. There was a significant difference between cholesterol, calcium, and magnesium levels in each two groups, but results showed no significant difference in total protein and albumin between the two groups. Overall, based on the results of this study it can be concluded that in natural environments, due to the weight of fish, there is little difference between the measured blood indexes.