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Background and Objective: Immobilization stress has a variety of effects on the enzymes activity. This study was conducted to determine the protective effect of Aloe vera extract on the serum level of creatine kinase enzyme in male rates exposed to acute and chronic immobilization stress. Materials and Methods: This experimental study was conducted on 45 male Wistar rats weighing approximately 200±30g. Animals were randomly allocated into 9 groups of 5 rats: control, normal saline, chronically immobilized, acutely immobilized, chronically immobilized normal saline, acutely immobilized normal saline, Aloe vera extract (600mg/kg/daily), acutely immobilized Aloe vera (600g/kg/daily) and chronically immobilized Aloe vera groups (600g/kg/daily). Aloe vera extract with a dose of 600mg/kg/BW was administered by gavage feeding before applying stress. For chronic immobilization, animals were put under immobilization stress for 2 hrs a day for 3 weeks and for acute immobilization animals were put under immobilization for 8hrs a day for one week. At the end of the experiments, blood samples were collected using cardiac puncture method and serum level of creatine kinase enzyme (units/L) was measured by spectrophotometery. Data were analyzed using SPSS-19, one-way ANOVA and Tukey post-hoc tests. Results: Serum level of creatine kinase enzyme represented a statistical significant increase in rats exposed to acute (2368.20±104.96 units/L) and chronic immobilization (2177.80±234.75 units/L) compared with control group (1240.40±706.40 units/L) (P<0.001). The enzyme alteration level was not significant in Aloe vera (1619.80±171.41 units/L), acutely immobilized Aloe vera extract (1619.00±206.03 units/L) and chronically immobilized Aloe vera extract (1448.00±106.07 units/L). Conclusion: This study showed that gavage of Aloe vera extract (600mg/kg/daily) in rats can prevent the elevation of creatine kinase enzyme activity resulted by immobilization stress.