Objective To observe the effects of different blood sampling sites on blood biochemical measurement in rats. Methods Blood samples were taken from different site of the rats. By using automatic biochemistry analyzer, a number of blood biochemical parameters were measured. Statistical analysis was performed to detect if there is significant difference among the values of blood samples taken from different sites in the rats. Results The values of some serum biochemical parameters obtained from samples taken from different sites differed significantly. The values of TP and ALB of blood taken from abdomial aorta or external jugular vein were significantly higher than those of blood taken from postcaval vein in the rats. The values of several parameters of the blood taken from orbital vein differed significantly from those from femoral vein blood samples. ConcIuslon It is important to unify the blood sampling sites in animals during chronic toxicity testing studies.