Sialic acid of seminal fluid of eighty two human subjects has been studied in relation to infertility. Normozoospermic group had highest sialic acid content (94 mgm/100 ml of the fluid) and was significantly different from other groups. The lowest sialic acid level was observed in necrozoospermic group (54 mgm/100 ml of the fluid). Azoospermic (62 mgm/100 ml) and vasectomised group (73 mgm/100 ml) had 33 and 22 percent less sialic acid level respectively than normozoospermic group. For the pooled observation sialic acid was found to be correlated (r = 0.282, significant at 5 percent level) with the total sperm count.