Purpose: To develop the method of chemical element (ChE) content measurement in samples of breast tissue (BT) using the activation by neutrons of nuclear reactor combined with the high-resolution spectrometry of gamma-radiation of short-lived radionuclides (INAA-SLR), and to investigate ChE contents in normal human mammary gland. Material and methods: In the samples of BT taken from female with intact mammary glands (mostly died from trauma, n = 38) the contents of calcium (Ca), chlorine (Cl), iodine (I), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), and strontium (Sr) were measured. To determine these element contents, the method of INAA-SLR was developed. Results: The accuracy of the developed method and the reliability of the results obtained in the study were confirmed by the measurements of international certified reference material IAEA H-4 Animal Muscles and the good agreement with data of its certificate. The main statistic parameters, including, arithmetic mean, standard deviation, standard error of mean, minimum and maximum values, median, percentiles with 0.025 and 0.975 levels was calculated for ChE contents in the normal BT. It was shown, for example, that means of mass fractions ± standard errors of means (M±SEM, mg/kg dry tissue) in normal human mammary gland were: Ca 128±14, Cl 1014±146, I 0,82±0,11, K 196±20, Mg 80,0±9,4, Mn 0,27±0,04, Na 665±71 и Sr 5,20±0,75. It was found that the Ca, Cl, I, K, Mg, Mn, Na и Sr contents in human mammary gland very differ from the normal level of these elements in whole blood, muscle and adipose tissue, particularly in contents of I and Sr. Conclusion: The method of INAA-SLR allow to obtain the representative data on Ca, Cl, I, K, Mg, Mn, Na и Sr contents in human BT specimen. It was shown, that such trace elements as I and Sr may be directly involved in the mammary gland function.