In this study, the effects of dietary administration of different levels of Cumin (Cuminum cyminum) ethanolic extract on some digestive enzymes activities and some serum parameters of Common carp juveniles (Ciprinus carpio) were examined. For this purpose, 150 juveniles of C. carpio (mean weight: 20.3±0.89 g) were randomly distributed in fifteen 300 liters fiberglass tanks (10 fish per tank). Five isonitrogenous and isocaloric diets were provided to contain 0 (as a control), 0.5, 1, 1.5 and 2.0 % of ethanolic Cumin extract. The fish were fed 3 times daily at 8:00, 13:00 and 17:00 based on satiation method for 8 weeks. At the end of the experimental period, the levels of digestive enzymes activities (Amylase, Lipase and Alkaline phosphatase) and some serum parameters (total protein, albumin, glucose, cholesterol, LDL, HDL, triglyceride, calcium, phosphorus) were analyzed. According to the results of these study, addition of different levels of Cumin ethanolic extract to juveniles of Common carp diet, significantly enhanced the digestive enzymes activities (Amylase, Lipase and Alkaline phosphatase) in treatments groups in comparison with the control group (P<0/05). In serum total protein, albumin, glucose and cholesterol in fish fed by cumin extract supplemented diets. Also, adding cumin extract to diet of C. carpio juveniles significantly (P<0.05) led to an increasing trend on serum phosphorus levels. There was not any significant difference between treated groups and the control group for calcium, triglyceride, LDL and HDL concentration. The levels of serum triglyceride and LDL in treatments groups were decreased. With increasing of cumin ethanolic extract also the levels of serum HDL and calcium in treatments groups were increased but these differences were not significant (P>0.05). According to the results of present study, diets containing cumin extract particularly in high doses can improve digestive enzymes activity and serum parameters of juveniles of Common carp. The treatment contain 1.5% ethanolic extract of Cumin seed has been suggested as the most appropriate supplementary level in the diet of juveniles Common carp (C. carpio).