In this study 43 calves (19 female and 24 male) from pure sistani cattle population were used in order to study the relationship between the calves' temperament at weaning time with performance, body type and some blood parameters. At weaning time, temperament was determined by using Pen Scores, Exit score and Chute Score methods. Calves were divided into three groups: calm, moderate and temperamental. The measured parameters included body temperature, heart rate, hand length, waist length, tail size, round the chest, the diameter of the hand and leg, forehead and the ear size as well as the concentration of glucose, total protein, creatinine, triglyceride, insulin, HDL, LDL, T3 and T4 in the serum. Statistical analysis of the results with R-3. 3. 2 software showed better growth rate and conversion coefficient in calm calves compared with other moderate and temperamental groups (P<0. 05). The heart rate in calm group was lower than in other two groups (P <0. 05) while the body temperature in calm group was lower than in temperamental group (P <0. 05). Moreover, the size of forehead, ear, waist, hand, hand and leg diameters in calm group was more than in temperamental group (P<0. 05) and the concentration of serum insulin in the calm group was higher than that in temperamental group (P<0. 05). Triglyceride, HDL, LDL, and glucose were lower in the calm group compared to temperamental group (P<0. 05). These results revealed that attention to behavior in breeding programs and selection, may be of considerable help in increasing livestock productivity in the long time.