Assessing the risks of nanomaterials exposure to consumer health requires studying their effect on metabolic processes in the body, in particular, on mineral homeostasis, the exchange of essential and toxic chemical elements. Nickel nanoparticles (NiNp) are used as components of hydrogenation catalysts, as well as pesticides. The aim of the work was to study the homeostasis of essential and toxic trace elements under the influence of oral administration to Wistar rats for 92 days of two types of NiNp with an average diameter of 53.7 and 70.9 nm at doses of 0.1, 1.0, and 10 mg/kg bw. In the liver, kidneys, and spleen the content of Ni, as well as 28 other essential, toxic and non-established biological function elements was determined by inductively coupled plasma mass spectrometry. In rats treated with NiNp, various changes in the indicators of homeostasis of trace elements were observed, including increased bioaccumulation of lead in the liver, gonads and brain, arsenic in the spleen, aluminum in the liver and brain. The introduction of nanoparticles lead to inhibition of the accumulation of divalent metal cations: Mg, Mn, and Sr - in the kidneys; Ba - in the kidneys and spleen; the content of Ca under the influence of nanoparticles increased in the kidneys, but decreased in the gonads. The effects on the bioaccumulation of trivalent elements Cr and B had different directions depending on the form of Ni in different organs. A number of effects exhibited by NiNp in animals were absent or had the opposite sign in the comparison group receiving Ni salt. The effects exerted by NiNp on microelement homeostasis should be taken into account in the toxicological assessment of their safety and health risks, especially in conditions of combined contamination of the habitat with heavy metal salts.