The local delivery of chemotherapeutic agents is a very promising strategy for the treatment of glioblastoma (GBM). Gemcitabine is a chemotherapeutic agent that has a different mechanism of action compared to alkylating agents and shows excellent radio-sensitizing properties. So, we developed an injectable gel-like nanodelivery system consisting in lipid nanocapsules loaded with anticancer prodrug lauroyl-gemcitabine (GemC12-LNC) in order to obtain a sustained and local delivery of this drug in the brain. In this study, the GemC12-LNC has been formulated and characterized and the viscoelastic properties of the hydrogel were evaluated after extrusion from 30G needles. This system showed a sustained and prolonged in vitro release of the drug over one month. GemC12 and the GemC12-LNC have shown increased in vitro cytotoxic activity on U-87 MG glioma cells compared to the parent hydrophilic drug. The GemC12-LNC hydrogel reduced significantly the size of a subcutaneous human GBM tumor model compared to the drug and short-term tolerability studies showed that this system is suitable for local treatment in the brain. In conclusion, this proof-of-concept study demonstrated the feasibility, safety and efficiency of the injectable GemC12-LNC hydrogel for the local treatment of GBM.