A review of n = 5216 semen analyses performed in our two Clinics from January 1986 to December 1989 allowed to identify n = 35 patients whose sperm had constantly very low motility (less than 5% progressive motile gametes in three subsequent analyses; necrozoospermia cases were excluded from this study). This apparently rare but severe anomaly was found to be associated not only with ultrastructural anomalies (n = 18), but also with positive seminal bacteriology (n = 8) or the presence of antisperm antibodies (n = 2). In eight cases the cause(s) for this constant asthenozoospermia remained obscure. The fertility potential of the men affected was followed-up and is discussed in relation to their anamnesis, physical exam and seminal characteristics.