Cadmium is a nonessential heavy metal and an industrial and environmental pollutant. It has been known that cadmium must enter cells to cause damage. To understand the transport systems responsible for cadmium entry into cells, it is important to determine the precise mechanisms underlying cadmium toxicity. Numerous studies have sought to unravel the exact pathways by which cadmium enters various cells and the mechanisms by which it causes toxicity in the organs of human and animals. The purpose of this review is to present the progress made regarding the mechanisms of cadmium transport in various cells and the mechanisms underlying cadmium toxicity in organs.