Hemicastration is followed by compansatory hypertrophy whereas unilateral testicular torsion is followed by atrophy in contralateral testicle in rats. Insulin-like growth factor (IGF-1) has important roles in testicular paracrine and autocrine functions. In this study it was aimed to compare ischemic parameters and IGF-1 levels in the contralateral testicle in unilateral spermatic cord ligation, testicular torsion, and hemicastratron. 32 wistar rats were equally allocated into sham, ligation, torsion, and hemicastration groups. In ligation group, right spermatic cord was ligated with 3/0 silk suture. In the torsion group, right testis was tcrsed for 720 degrees. In hemicastration group, right orchiectomy was done. 48 hours later left orchiectomy was done in all groups. Malondialdehyde (MDA) and IGF-1 levels were determined in the testicle. Average values of the groups were compared with Anova followed by Dunnett T3 multiple comparison tests. MDA levels were significantly reduced in ligation and torsion groups (p < 0.05). This reduction was more prominent in hemicastration group (p < 0.05). Contralateral testicular IGF-1 levels in ligation and torsion groups were not different compared with the sham group. Left testicular IGF-1 level in the hemicastration group was decreased significantly compared with other groups (p < 0.05). Histological. changes evaluated. Contralateral Johnsen's testicular biopsy scores were significantly decreased in all experimental groups but mean tubular diameter was not changed in all groups. © 2004 Kluwer Academic Publishers.