Abstract: Objective: To detect whether tumor-associated monoclonal antibodies can be used to enhance photodestruction of human ocular melanoma cells. Methods： Monoclonal antibody IG12 conjugated photosensitizer chlorin e6 mono-ethylenediamine onoamide (CMA) and evaluated the effectiveness of this immunoconjugate (McAb-CMA) in the destruction of OCM431 human ocular melanoma cells in vitro. RPMI1846 melanoma cells were used as non-target cells. Argon pumped dye laser was turned to 654nm, coupled to a 1mm quartz fiber optic and spot size was 35mm. Both target and non-target cells were treated with IC or light alone, Cell survival was assessed by colorimetric assay tetrazolium salt MTT. Results：Target cell (OCM431) preincubated with IC and irradiated with 5-40J/cm2 showed light dose-dependent decrease in cell survival. Under same light dose, cell survival decrease by increase McAb-CMA dose from 5.2!M to 6.7!M. Non-target cells (RPMI1846) showed much less phototoxicity; cell survival was 74±2.6(. Conclusion: These results show that McAb-photosensitizer immunoconju-gate is effective to enhance photodestruction of human ocular melanoma cells in vitro.