In order to explore the impact of surgical treatment on antioxidant defense system in varicocele (VAR), we evaluated seminal total antioxidant capacity (TAC) in 25 patients affected by VAR, in 14 patients studied 10-24 months after varicocelectomy (post-VAR) and separated into normo- and oligospermic groups, and in 24 non-VAR control patients with seminal parameters matched to patients with VAR in the oligo- and normospermic groups (7 subjects with idiopathic oligospermia and 17 normal fertile subjects). TAC was measured in seminal plasma with the system H(2)O(2)-metamyoglobin as a source of radicals, which interact with a chromogen 2,2',-azinobis (3-ethylbenzothiazoline-6-sulphonate) (ABTS), generating a radical cation spectroscopically detectable. The presence of antioxidants induces a lag time in the production of ABTS cation proportional to the concentration of antioxidant compounds. When whole groups of patients were analyzed, lag values were significantly higher in VAR vs non-VAR controls (mean +/- SEM, 106.6 +/- 8.8 seconds vs 78.7 +/- 8.8 seconds) but were not modified by surgery (mean +/- SEM, 105.8 +/- 8.6 seconds). In groups separated according to seminal parameters, oligospermic VAR presented significantly higher lag values than oligospermic controls. Finally, when exploring a possible association of TAC with seminal parameters, we found a significant correlation between lag and sperm motility only in patients with VAR who were in the normospermic group (r = 0.65, P <.01). This correlation was not yet manifest post-VAR. In conclusion, surgical treatment does not seem to modify absolute values of TAC but influences its fine regulation and relationships with sperm motility.