Bee-collected pollen is reported as a health food with a vast range of nutritional and therapeutic effects. Biochemical (glucose, total protein, creatinine, urea, triglycerides, total cholesterol, ALT, AST, LDH, ALP, chloride, sodium, potassium and total antioxidant status) and hematological (total leucocyte count, erytrocyte count, hemoglobin, hematocrit, MCV MCH, MCHC) parameters in blood of rainbow trout (Oncorhynchus mykiss) treated to various pollen concentrations (0.5, 2.5, 5, 10, 20 and 30 ppm) for 96 h were determined. The results of this study demonstrated that the levels of total protein, creatinine, chloride and sodium in blood of fish which treated to different concentrations of pollen were not changed (P>0.05) compared with control group. In this study, the highest total antioxidant capacity of pollen was determined at 10 ppm concentration, but serum paraoxanase (PON) activities were not observed. It is concluded that concentration-dependent effects of pollen on blood of fish can be favorable in prevention of diseases.