The gallium(III) complexes [Ga(2Am4DH) 2 ]NO 3 (1), [Ga(2Am4Me) 2 ]NO 3 (2) and [Ga(2Am4Et) 2 ]NO 3 (3) were prepared with 2-pyridineformamide thiosemicarbazone (H2Am4DH) and its N(4)-methyl (H2Am4Me) and N(4)-ethyl (H2Am4Et) derivatives. The thiosemicarbazones were cytotoxic against malignant RT2 glioblastoma cells (expressing p53 protein) with IC 50 values in the 7.3–360μM range, and against malignant T98 glioblastoma cells (expressing mutant p53 protein) with IC 50 values in the 3.6–143μM range. Coordination to gallium strongly increased the cytotoxic potential in complexes 2 and 3, which showed IC 50 values in the 0.81–9.57μM range against RT2 cells and in the 3.6–11.30μM range against T98 cells, and were 20-fold more potent than cisplatin. All thiosemicarbazones and gallium complexes were able to induce cell death by apoptosis.