Introduction: Chronic exposure to aflatoxin can lead to complications such as liver failure and cancer. There are many factors that affect aflatoxin occurrence. This study aimed to assess the association between sociodemographic factors and the knowledge, attitude and practice towards aflatoxin with urinary aflatoxin M1 occurrence among residents in Hulu Langat district, Malaysia. Methods: This was a cross-sectional study conducted among healthy Malaysian adults aged 18 to 60 years residing in Hulu Langat district, Malaysia. Socio-demographic background and the knowledge, attitude and practice of respondents towards aflatoxin were assessed through questionnaires. Non-fasting urine sample (15 ml) was collected in the morning and urinary aflatoxin M1 level was quantified. Results: Of the 444 healthy Malaysian adults, 199 urine samples were detected with aflatoxin M1. From 37 positive samples with aflatoxin M1 level above detection limit (0.64 ng/ml), mean value was 1.23±0.91 ng/ml (range = 0.65-5.34 ng/ml). Urinary aflatoxin M1 occurrence was significantly different across ethnicity, age group, monthly household income, attitude and practice towards aflatoxin. Binomial logistic regression confirmed ethnicity and monthly household income as factors contributing to urinary aflatoxin M1 occurrence. Chinese were 3.20 times more likely to have aflatoxin exposure than non-Chinese. Detected urinary aflatoxin M1 was more common among household with a monthly income above RM1,500. Conclusion: The results provided an insight to explain the variation in aflatoxin occurrence among the population.