Malignant pleural mesothelioma is known to be widely resistant to therapy and new treatment strategies are needed. Curcumin, which has a long history as a dietary spice is known to suppress the growth of multiple cancer lines, but the effects on mesothelioma cells are not well defined. In the present study we examined the effects of curcumin on ACC-MESO-1, which is a human derived mesothelioma cell line. We found that curcumin dose-dependently reduced cell viability but did not induce apoptosis. Curcumin administration increased LC3B-II/LC3B-I expression, and induced the formation of autophagosomes on electron microscopy. These changes were attenuated by RNA silencing of atg5. From these findings it was speculated that induction of autophagy was at least in part involved in the reduction of cell viability by curcumin. Copyright © 2012 John Wiley & Sons, Ltd.