PURPOSE: This study investigated the additive effect of photodynamic therapy (PDT) plus traditional radiotherapy (RT) for patients with breast cancer and chest wall recurrence. METHODS: A total of 40 patients with recurrent breast cancer were prospectively randomized to receive RT alone (group A, n=20) or PDT and RT in combination (group B, n=20). Traditional RT at a dose of 50 Gy was delivered in 25 fractions with or without exposure to 5-aminolevulinic acid and red light as PDT. RESULTS: The response rates were not statistically different between the groups, but more patients achieved a complete response (CR) in group B (50%) than in group A (20%). The median time to CR in group B was significantly shorter than that in group A (109.6 days vs. 175.2 days, p=0.001). Adverse event profiles were not different between the groups. CONCLUSION: An additive antitumor effect is demonstrated with additional PDT to RT. This combination therapy might reduce the duration of exposure to RT, but further investigation is warranted.