The aim was to carry out a survey of aflatoxin M₁ (AFM₁) in raw whole milk from bulk tanks. The sample collection was performed in farms located in one the most important milk-production zones in the centre of Argentina. A total of 94 samples of milk from 47 dairy farms were analysed. AFM₁ analysis involved the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) with prior purification of the extracts using immunoaffinity columns. AFM₁ incidence in raw milk was high as 63.8% and levels were between not detected to 0.07 µg l⁻¹. Several contaminated samples (39%) were over the European Commission limit for infant milk (0.025 µg l⁻¹), although none of samples were above Argentine legislation. Estimates of AFM₁ intake were assessed for different age populations. The average AFM₁ estimated daily intakes were 1.6, 0.5, 0.17 ng kg⁻¹ body weight day⁻¹ for 4-year-old babies, young children, and adults, respectively. All tested farms used pastures and silages at similar composition. Even though some farms (13) employed high-risk supplementary feeds, such as peanut pod and/or cotton seed, no statistically significant differences were observed between groups. Information from AFM₁ levels in milk in Argentina is limited. A systematic AFM₁ monitoring programme must be performed by means of accurate and reliable analytical techniques as a strategy for protecting milk consumers.