Regardless the form, nickel is an element commonly used. Its numerous advantages make it irreplaceable in many industries. The widespread use of this element in different branches leads to increasing nickel penetration to the environment and its pollution. Furthermore, the contamination of environment results in affecting the living organisms, including both plants that are directly exposed to Ni in soil, water or air, and humans whose exposition to Ni is direct (e.g. contaminated air) and/or indirect (e.g. food with high amount of Ni). Therefore, the exposition of living organisms to Ni may constitute a threat. This paper constitutes the short review of nickel as an environmental contaminant with characterization of its main sources in the environment. The nickel nanoparticles have been also studied. The influence of Ni and its nanoparticles on living organisms with emphasizing its allergenicity of human has been described.