In animal studies, exposure to persistent organochlorine pollutants (POPs) in utero and through mother's milk has been suggested to affect the onset of puberty. However, human studies are scarce and ambiguous. In the present study, information on age at menarche was collected from 545 women who had been brought up in a fishing village/family on the Swedish east coast, off the Baltic Sea, and therefore were assumed to have been exposed to POPs in utero, through breast feeding, and/or through dietary habits during their childhood. The average age at menarche for these women was compared to that of three referent groups: (a) 1252 women who also had been brought up in a fishing village/family, but on the Swedish west coast, where the fish had been considerably less contaminated; (b) 634 women from the east coast, but who had not grown up in a fishing village/family; and (c) 869 women from the west coast who had not grown up in a fishing village/family. Based on previous studies, all groups were regarded as having similar socioeconomic circumstances. Data were analyzed using analysis of variance (ANOVA). In an attempt to account for variations in environmental concentrations of POPs over time, all analyses were adjusted for year of birth. Exposed women were found to be slightly older at menarche than referent women from the same coastal area (mean age 13.0 vs 12.8 yr). No differences were found between the exposed women and the two other referent groups (mean age 13.0 yr in all groups).