Photoacoustic tomography (PAT) is an emerging molecular imaging modality. Here, we demonstrate use of semiconductor copper sulfide nanoparticles (CuS NPs) for PAT with an Nd:YAG laser at a wavelength of 1064 nm. CuS NPs allowed visualization of mouse brain after intracranial injection, rat lymph nodes 12 mm below the skin after interstitial injection, and CuS NP-containing agarose gel embedded in chicken breast muscle at a depth of ~5 cm. This imaging approach has great potential for molecular imaging of breast cancer.