Photoacoustic therapy using the large photoacoustic effect of agents for selectively killing cancer cells is demonstrated. Herein, a highly efficient photoacoustic treatment using gold nanorods (AuNRs) and its antitumor effect are reported. Folic acid conjugated AuNRs are designed to specifically target folate receptor-expressing cancer cells. Following photoacoustic treatment, most of the cancer cells with intracellular AuNRs die within 20s. Compared with single-walled carbon nanotubes and indocyanine green containing nanoparticles, AuNRs can produce much stronger shock waves by absorbing the optical energy and thus induced the more efficient cell death at equal molar concentrations. In addition, the laser-induced shock waves can be detected for photoacoustic imaging. Our in vivo experiments demonstrated that the AuNR-mediated photoacoustic treatment resulted in efficient tumor suppression in mice. Thus, both efficient cancer cell diagnostics and selective photoacoustic treatment can be realized with a single-particle formulation. Nanotechnology has enabled the development of many novel methods for the treatment of cancer. One of these is photoacoustic therapy. In this article, the authors demonstrated the efficacy of Folic acid conjugated gold nanorods in killing cancer cells after photoacoustic treatment. The findings should provide impetus for future clinical studies.