Intrathecal chemotherapy has been the mainstay treatment for meningeal carcinomatosis for decades. However, this has not been the case with non-small cell lung cancer (NSCLC), due to the low efficacy of the drugs that could be used before. Gemcitabine is an effective drug against NSCLC and has a structure similar to cytarabine, which has been widely used in intrathecal chemotherapy. Thus, intrathecal gemcitabine chemotherapy might prove to be suitable for leptomeningeal carcinomatosis induced by NSCLC. We herein report our experience using gemcitabine intrathecal injections in a NSCLC patient with leptomeningeal carcinomatosis.