Criteria for improved semen quality after varicocele operations are not clear, as they do not express sperm fertilization capacity, its most important qualification. Twenty-two couples, 12 with mechanical female infertility (group I) and 10 with normal female fertility (group II), in whom the husband had subfertile semen in the presence of varicocele, and who had failed preoperative in vitro fertilization-embryo transfer (IVF-ET) attempts, were readmitted for the IVF-ET procedure following the repair of varicocele. In group I, a 20% pregnancy rate was achieved after the operation, while no pregnancies occurred before surgery. In group II, four pregnancies (40%) were achieved after operation. Plasma testosterone (T) levels demonstrated a significant increase in 50% of the patients in both groups after surgery, resulting in a concurrent improved fertilization, cleavage, and pregnancy rates.