Summary The testicular function of 47 men who had been treated by MOPP chemotherapy for a Hodgkin's disease was studied in a long-term survey. Azoospermia was constant during at least 14 months after completion of the treatment. After a follow-up period of 89.4 ± 54.7 months, 26 men were still azoospermic. No correlation could be found between the therapeutic regimen and the results of semen analysis. For the same treatment, some men recovered spermatogenesis within 5 years, others after more than 10 years while some were still azoospermic after 20 years. However, the association of infra-diaphragmatic irradiation to high dose MOPP therapy had a profound detrimental effect on spermatogenesis: only 3/13 men recovered. Sperm recovery was often incomplete: 17/21 men had a sperm count below 20 million ml-1. Yet, spontaneous pregnancies were obtained with severe oligozoospermia: only 1/11 sperm counts performed close to fertilization exceeded 20 million ml-1, and 8 were below 5 millions ml-1. FSH failed to be either a sensitive or a specific marker of sperm recovery, a discrepancy between FSH level and spermiogram being noticed in 18.2% of cases.