Autophagy is a process in which subcellular membranes undergo dynamic morphological changes that lead to the degradation of cellular proteins and cytoplasmic organelles. Autophagy is closely associated with many diseases, and plays a role in the development of cancer. On one hand, autophagy and cell death process may suppress the development of tumours; on the other hand, autophagy is a self-defence mechanism, which may protect the tumour cells from injury caused by nutrition deficiency, ionizing radiation and chemotherapy during tumour development. In this review the mechanisms that link autophagy to tumour suppression and promotion are discussed.