Compared with chemotherapy and radiotherapy, hypothermia is a less invasive cancer treatment technique.However,the efficiency of conventional hypothermia is very limited due to the diffusive nature of heat.Localized thermal treatment of tumors particularly those present deep inside a body is more difficult.Near infrared (NIR) laser is a promising tool for biomedical applications due to its high penetration depth.However, its efficiency for cancer treatment is very low due to the limited NIR light absorption by tumors.Therefore, to improve the efficiency of laser ablation,it is imperative to increase the light absorption by tumors.In recent years, nanoparticle-assisted photothermal therapy has been proven to be efficient for thermal treatment of cancer cells, which has been demonstrated by numerous in-vitro and in-vivo studies.By functionalizing the nanoparticles with suitable cancer targeting ligands, the nanoparticles can accumulate in malignant tissues.Upon the delivery of laser to the tissues, localized heating and tumor ablation can be achieved.With the presence of nanoparticles, the laser energy fluence can be reduced to below medically safe levels.The nanoparticles with photothermal properties include metallic nanoparticles such as gold nanoparticles and nanoparticles of carbon materials, such as carbon nanotubes and graphene nanoparticles.These nanoparticles also have interesting optical properties, which eliminates the use of additional fluorescent biomarkers.In this talk, I will give an overview of the progress of nanoparticle-assisted photothermal therapy, with a focus on my own research.