Everything that has originated in this world will have to ends its journey of life. However in biological system this journey is previously programmed and this programming maintains the cells to carry out its all vital activities and after certain time, this journey ends to its final destination, i.e., death. However in case of simple unicellular organism, this journey is too simple and is controlled by the programming in the organism it self. But in case of large multi-cellular organism, where the cells are the building block of multi-cellular architecture, each and every cell is in continuous contact with other cells. Journey of the cell is influenced by its neighbors, so this programming becomes too much complicated in case of higher organisms. Usually when cell die, the death may take place by three means. First, the death of cell after completing its journey of life by Apoptosis. Second, death arises due to injury i.e., necrosis. This is simply like, death of a person, after aging and before aging by accident. Third situation is intermediate to both that is paratopsis. Within all these types of cell death, only apoptosis is truly programmed cell death that takes place due to execution of cell death program. This programming is regulated by the various cellular messenger, stimulator and positive and negative regulator of apoptosis. This review covers basic regulation of apoptosis machinery. Understanding of these pathways can aid in the understanding of molecular biology of cancer, AIDS and various other diseases.