Copper based nanoparticles (NPs) have attracted increased attention for biomedical applications. Copper chalcogenide NPs exhibit strong absorption in near-infrared region, demonstrate highly efficient light-to-heat transformation under near-infrared laser irradiation, and cause selective thermal destruction to the tumor. Smaller copper NPs display fluorescence signal and capability for optical imaging. Copper based NPs also serve as a versatile vehicle for drug delivery and image-guided therapy. This review covers recent advances related to the biomedical application of copper based NPs, with a focus on cancer imaging and therapy. We also discuss challenges to their successful clinical translation.