Medico-social factors such as type of infertility, sexually transmitted diseases (STD), drug abuse, erectile dysfunction, divorce, and polygamy were evaluated among 64 infertile men (i.e. 32 oligo-asthenozoospermic and 32 azoospermic) and 23 men of proven fertility in Jos University Teaching Hospital, Jos, Nigeria. Of the 64 infertile men, 27 (42%) and 37 (58%) had primary and secondary infertility respectively. A history of STD, indicated by purulent urethral discharge, was recorded among 40 (63%) with 22 (55%) of this number having had repeated exposures to STD. While 17 (43%) of the infected infertile men were treated by qualified medical doctors, 23 (57%) either had self-medication or received treatment from quacks. Five (8%) of the 64 infertile men used hard drugs, 11 (17%) had erectile dysfunction, 15 (23%) were re-married due to broken marriage relationship or divorce, and 7 (11%) were polygamous. All the fertile men were monogamous with no history of either erectile dysfunction or usage of hard drugs. One (4%) of the fertile men had a history of a broken marriage relationships. Six (26%) had a history of STD with 5 (26%) of them having received treatment from qualified medical doctors. Although the study population is small, the results obtained in this study reveal higher incidences of STD, marital instability, and multiple marriage partnerships (polygamy) among infertile men than the fertile in Jos.