Metalloids have vital importance for some organisms. The particular relationship between the metalloid and specific biological functions should be investigated further, though there are somewhat limited scientific studies on the subject. Among the roles of this specific class of chemical elements, silicon, for instance, plays an important role in the formation of valve structures in diatoms. Boron is an essential element for plants and known to be toxic for living cells when present above a certain threshold. Arsenic and antimony are toxic metalloid elements in numerous respects. Therefore, the cells have developed biochemical and molecular strategies to protect and escape from these metalloids. Another metalloid, germanium, is one of the rare elements and although its inorganic form is toxic, its organic form is used to treat many diseases. Studies have shown that there is a high proportion of Germanium metalloid in the structure of Ganoderma lucidum used in the treatment of some diseases. In addition, tellurium-containing proteins were found in the structure of some tellurium-resistant fungi. Thus, considering all this information collectively reflects the significance of the metalloids in biological life. The aim of this study is to present the importance and roles of some metalloids in biological life.