Lead concentrations was measured in samples of mineral mixtures used in beef cattle feed in the states of Sao Paulo, Parana, Mato Grosso and Mato Grosso do Sul, Brazil. Lead content was determined by inductively coupled plasma atomic emission spectrometry. Of the 60 analyzed samples, 21 had values greater than 30 ppm (range less 1.6 to 460 ppm), which is the maximum concentration recommended [3,14]. These findings show the necessity for careful industrial monitoring because some mineral mixtures contain sufficient lead to cause toxicity in animals.