Curcumin, a naturally occurring phenolic compound, is a highly potent anticancer agent against many different types of cancers. Recent studies show that curcumin can be used as a photosensitizer in photodynamic therapy for cancer treatment. However, the major disadvantage of curcumin is its poor aqueous solubility. To improve its applicability in cancer therapy, we intercalated curcumin into layered double hydroxide (LDH) with the co-precipitation method and used as a nanohybrid photosensitizer in photodynamic therapy of human breast cancer cells. Powder X-ray diffraction (XRD), TEM and SEM microscopy analyses indicate that curcumin is stabilized in the host interlayer. According to the spectroscopy results, the water solubility and dispersity of intercalated curcumin increased and loading amount of curcumin in LDH is about 50%. The photodynamic effect of curcumin and the curcumin–LDH nanohybrid was studied on the MDA-MB-123 human breast cancer cell line. Optimization of incubation time with free curcumin and curcumin–LDH nanohybrid as the most effective parameter was investigated. The optimum irradiation time of blue LED on photodynamic therapy was determined for both free curcumin and curcumin–LDH nanohybrid. Cell viability studies revealed that the nanohybrid curcumin–LDH were able to show more effective photodynamic effects on the cancer cells as compared to free curcumin. These results suggest that the biocompatible layered double hydroxide can be used as the basis of a tunable curcumin delivery carrier for photodynamic therapy in breast cancer treatment.