The goal of this review is to introduce the reader with basic mechanisms of apoptosis and the main functions of programmed cell death in multicellular organisms. Apoptosis is a programmed process of cell death accompanied by activation of caspases, cysteinyl aspartate – specific proteases. There are two main pathways of apoptosis – intrinsic and extrinsic. Intrinsic pathway begins with permeabilization of outer mitochondrial membrane, while extrinsic pathway begins with binding of signal molecules to death receptors in cell membrane. Apoptosis plays a great role in correct development of organisms. Apart from its role in keeping the balance between newly-formed and dying cells, it is also one of the main initiators of morphogenesis and tissue reorganization. Upregulated or downregulated apoptosis of some cells is one of the main causes of ageing. Programmed cell death is a complex process that can be regulated on many levels, and misregulation of that process can often lead to an occurrence of illnesses. Direct targeting of apoptotic mechanisms could hold the key to curing cancer, which makes researches of this topic very significant.