Autophagy is an evolutionarily conserved catabolic process crucial for development, differentiation, survival, and homeostasis. However, if it proceeds to completion, autophagy can lead to cell death. Changes in macroautophagy activity have been described in cancer cells and in solid tumors, and inhibition of macroautophagy promotes tumorigenesis. The review focuses on the importance of autophagy in tumour development and cancer therapy. We summarize what is currently known about autophagy, and discuss its role in cell death and survival. We discuss possible mechanisms underlying the anti-tumor activity of autophagy. We also discuss the effect of autophagy modulation in cancer therapy.