Delay in the diagnosis of spermatic cord torsion (SCT) is still a significant cause of testicular loss in children. The aim of this experimental study was to assess the diagnostic value of serum creatine kinase (CK) in the early period following SCT. Forty male rats were assigned randomly into five similar groups: group A, control; group B, sham, right testis exposed, manipulated, and blood sampling at 6th h; group C, right SCT, blood sampling at 2nd h; group D, right SCT, blood sampling at 4th h; and group E, right SCT, blood sampling at 6th h. CK and its isoenzymes were measured in the sera of all animals. All testes were removed and examined histopathologically. Significant increases in serum CK levels compared to control and sham groups were observed at 4 and 6 h following SCT. The major increase in CK was observed in the CK-MM isoenzyme fraction. Histologic pictures showed varying degrees of edema, vascular congestion, and hemorrhage in the testicular tissue, but no necrosis in any of the study groups. These results showed that serum CK levels in rats in the early period following SCT increase significantly before necrosis of testicular tissue. This may be of value as a diagnostic test, to corroborate findings from clinical studies.