Unexplained male infertility is a condition in which infertile men have normal semen analyses on multiple occasions with no obvious physical or endocrine abnormality when female partner infertility has been ruled out. In addition to erectile problems and coital factors, immune causes and dysfunctional sperm may contribute to such condition. Contemporary andrology may help analyze the unexplained male fertility problem on the basis of cellular and sub-cellular mechanisms and select the proper management. This review highlights the concept of unexplained male infertility and discusses the potential causes and its proper management in the era of modern andrology and assisted reproductive techniques.