Numerous gold nanostructures have the potential for photothermal therapy in cancers. Here, gold nanocages and gold nanoshells are synthesized, the sizes of which are fine-tuned for a response at 750 nm wavelength. Their photothermal therapeutic efficiency is compared at gold concentration of 100 lg mL -1 using a near-infrared laser (750 nm). The biocompatibility for varying concentrations of gold (1 to 100 lg mL-1) is performed in a normal cell line and laser-mediated cell cytotoxicity for varying time intervals (7.5 and 10 min) is carried out in breast cancer cells. This study shows that when analyzed under similar conditions, the gold nanocages show better biocompatibility and are more efficient in near-infrared absorption and photothermal conversion in comparison with conventional gold nanoshells. When subjected to photothermal laser ablation of breast cancer cell line for 7.5 min and 10 min, the nanocages are able to induce 62.92 ± 3.25% and 96.41 ± 3.04% reduction in cell viability, respectively, in comparison to nanoshells, in which a 43.35 ± 1.91% and 79.89 ± 4.74% reduction in cell viability is observed. The current study shows that the gold nanocages can outperform gold nanoshells and effectively kill cancer cells without any significant cytotoxic effect on normal cells. New-generation nanomaterials, such as gold nanocages, are emerging as promising agents in photothermal therapy of cancer alongside conventional ones, such as gold nanoshells In the current analysis, the gold nanocages appear preferable for photothermal therapy based on their biocompatibility, photothermal efficiency, and near-infrared laser-mediated tumor cell ablation properties. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.