The high incidence rate of breast cancer and the unpleasant side effect that often occur in chemotherapy, radiation therapy and surgery that can be overcome by photodynamic therapy. PDT threatment uses a relatively safe photosensitizer and has selectivity in cancer cells. The purpose of this research to find out anticancer activity of cobalt (II) phthalocyanines as fotosensitizer for PDT. This research was conducted a dark toxicity test and PDT activity at 24 and 48 hours incubation against breast cancer cells (T47D). This research uses the MTT assay method with a 24 hour at 37 oC and 5% CO2. Cobalt (II) phthalocyanines included almost non-toxic in the dark toxicity test. Cobalt (II) phthalocyanines activity by PDT at 24 and 48 hours incubation respectively 219.359 μM which included very weak toxicity and 49.359 μM included weak toxicity. However cobalt (II) phthalocyanines can be potential for PDT.