PURPOSE To evaluate the variance of apoptosis in rats in which experimental varicocele was induced, and then treated by varicocelectomy. MATERIALS AND METHODS Forty, adult male, Wistar albino rats were used in this experimental study. Experimental varicocele was created in thirty rats as Saypol et al described. Five rats underwent a sham operation while the remaining five rats were the control group. Five rats from the varicocele group were sacrificed on the 14th postoperative day and five more were sacrificed on the 28th postoperative day to document the level of apoptosis due to varicocele. Varicocelectomy was performed on twenty rats with varicocele on the 14th postoperative day. These twenty rats were divided into four groups to evaluate the level of apoptosis in their testis after varicocelectomy. They were sacrificed on days 7, 14, 21and 28 post varicocelectomy. The testes were fixated by perfusion with 10% formaldehyde and then placed in paraffin blocks. From each testis, two samples were stained with hematoxylene + eosin and two samples were stained using the Tunel method. In each specimen apoptotic germ cells stained by Tunel was counted in the cross section of 100 seminiferous tubules. The apoptotic index was defined by calculating the number of apoptotic cells per seminiferous tubule. Apoptotic Index = Total Apoptotic Germ cell count / 100. RESULTS In the adult rats on which experimental varicocele were performed, both in the second and 4th week, apoptosis in both left and right testes were significantly higher compared to the control group (with varicocele day 14:0,25-0,26, with varicocele day 28: 0,28-0,32, Control: 0,11-0,13). After varicocelectomy on the 7th and 14th day the slight increase in the level of apoptosis continued (day 7: left testis 0,30 - right testis 0,28, day 14:left testis 0,25 - right testis 0,31). After varicocelectomy, the apoptosis decreased significantly on day 21 (left testis 0,16 - right testis 0,22), and on day 28 it was almost equal to the level of the control group (left testis 0,14 - right testis 0,16). CONCLUSIONS After the creation of unilateral varicocele, the level of apoptosis increased in both the left and right testes. Apoptosis in both testes decreased after surgical treatment.