Background: Oncolytic viral therapy and photodynamic therapy are potential therapies for inoperable or advanced pancreatic cancer. Our aim was to investigate the anti-cancer killing effects of reovirus therapy combined with protoporphyrin IX (PpIX)-mediated photodynamic therapy on a variety of human pancreatic cancer cell lines. Methods: Pancreatic cancer cell lines (PsPC-1 and BXPC-3) and a non-cancer control cell line (HEK293) were infected with reovirus serotype 3 strain Dearing (T3D) at 0, 0·1, 1, and 10 plaque-forming units (PFU) per cell for 48 h. Cells were incubated with PpIX pro-drug 5-aminolevulinic acid (5-ALA) at 0, 1, 2, 3, and 4 mM for 4 h. Then, cells were photo-irradiated for 15 min with visible red light-emitting diodes with a light-fluence of 0·54 J/cm2 of 653 nm (PpIX optimal excitation wavelength). The killing effects of reovirus combined with PpIX-mediated photodynamic therapy were analysed in methylthiazoltetrazolium (MTT) and trypan blue assays. The effect of adding reovirus after photodynamic therapy was also assessed. The statistical significance of the difference between groups was assessed with the two-tailed Student's t test. p