Toxic metals are one of the significant groups of chemical contaminants that humans are exposed to by oral, inhalation, and dermal routes. Exposure to these chemicals begins with intrauterine life and continues during lactation period at the first years of life. Breastfeeding has a much more special place than other nutrition options for infants. However, when possibility of contaminant transfer by breast milk is considered, its safety and quality is essential. Regarding infant and mother health and limited number of information on this field in Turkey, measuring contamination levels in breast milk is important. Therefore, in the present study, lead (Pb), cadmium (Cd), nickel (Ni), and arsenic (As) levels were measured by atomic absorption spectrometry in 64 breast milk samples obtained from mothers from Ankara, Turkey. Pb and Ni levels in breast milk samples were found to be 391.45 +/- 269.01 mu g/l and 43.94 +/- 33.82 mu g/l (mean +/- SD), respectively. Cd was found only in one of 64 samples, and the level was 4.62 mu g/l. As level was below the limit of quantification (LOQ, 7.6 mu g/l) in all samples. These findings will accurately direct strategies and solutions of protection against contaminants in order to reduce their levels in biological fluids.