Objective To evaluate the effectivness of photodynamic therapy (PDT) with chloroaluminum sulfonated phthalocyanine (CASPc) in B16F10 melanomas in a rabbit model. Methods B16F10 murine melanoma tumor fragments were implanted transclerally into the subchoroidal space of 38 immunosuppressed New Zealand albino rabbits and examined with indirect ophthalmoscopy and ultrasonography. When the tumors ranged from 2.0~3.8 mm in height, 30 rabbits were treated by PDT, with intravenous injection of CASPc 5 mg/kg, and irradiation at the wavelength of 675 nm of an argon-pumped dye laser after 24 hours. Light dose ranged from 20 J/cm2 to 70 J/cm2. The other 8 animals were treated with light only or photosensitizer only. The animals were followed up for 6~8 weeks. Results The 30 tumor-bearing rabbits were by PDT (laser and CASPc) regressed in 21 animals after treatment. At light doses under 40 J/cm2, tumor regrowth was observed in 9 animals after two weeks of treatment. In all of the 8 control animals, the tumor-bearing eyes were filled with tumor at the third week after implantation with laser doses of 70 J/cm2. Conclusion The study suggest that CASPc PDT may be effective in the treatment of B16F10 choroidal melanomas.(Chin J Ocul Fundus Dis，2004，20：67-132)