RESUMENEl presente estudio tuvo como objetivo evaluar la presencia de aflatoxinas M 1 en muestras de leche fresca de establos de la cuenca de Arequipa. Se colectaron muestras de 10 establos lecheros de las irrigaciones de Santa Rita, Majes, La Joya y Lluta en 2 periodos (verano e invierno) del año 2008. Los establos se clasificaron en intensivos y extensivos de acuerdo al sistema productivo empleado. No se obtuvo ninguna muestra de leche contaminada a aflatoxinas M 1 , siendo un indicativo de que la presencia de este metabolito en leche no constituye un problema en la zona de estudio.Palabras clave: aflatoxina M 1 , leche, establo, Arequipa ABSTRACTThe aim of the present study was to evaluate the presence of aflatoxin M 1 in raw milk samples from dairy farms of Arequipa milkshed. Milk samples were collected from 10 dairy farms located in the irrigated area of Majes, Santa Rita, La Joya and Lluta districts in two seasons (summer and winter) of 2008. Milk farms were classified as intensive and semintensive according to their productive system. Zero positive milk samples were obtained during the study and therefore, it is concluded that aflatoxin M 1 is not a contaminant of fresh milk in the region.