Aflatoxin M₁ (AF M₁), a hydroxylated metabolite of AF B₁, is an important toxin that can contaminate the milk of lactating mothers. A correlation study was conducted to determine the relationship between AF M₁ content of breast milk, dietary exposure to AF B₁ and socioeconomic status of lactating mothers in the three Senatorial districts of Ogun State, Nigeria. Equal amounts of breast milk (20ml) and food rations (40kg) obtained from 50 volunteer lactating mothers and eighty-two frequently consumed food commodities in the preceding month were used for the study. The level of contamination of the foods by AF B₁ was low (0.16–0.33μg/kg) and differed significantly (p<0.05) across the state but did not exceed the EU limit of 2μg/kg. The occurrence level of AF B₁ was however high (93.75–94.45%) and was more pronounced in Ogun East Senatorial district (94.45%). Eighty-two percent of the breast milk was contaminated with AF M₁ (3.49–35ng/l) and 16% exceeded the EU limit of 25ng/l while a 100% occurrence risk was recorded in Ogun Central Senatorial district. The socioeconomic status of the mothers also significantly influenced their dietary exposure and exposure risk of the sucklings to AF M_1.