Fifteen percent of men in the general population are estimated to have varicoceles, which are diagnosed in 40% of men presenting for fertility assessments. Approximately 1% of men in the general population are found to be azoospermic, and 15% of men presenting for fertility assessments are azoospermic. This chapter reviews the effect of varicoceles on testicular function in men with azoospermia, the impact of varicocele repair on the semen parameters of azoospermic men, and the impact of varicocele repair on sperm retrieval and pregnancy outcomes when sperm does not return to the ejaculate of the male partner who undergoes varicocele repair for azoospermia.