Meningeal carcinomatosis commonly referred to as carcinomatous meningitis (CM), is the third most common central nervous system (CNS) metastatic complication of systemic cancer and is the most morbid of CNS metastases. The disease is challenging to treat for a variety of reasons not least are challenges in making a diagnosis of CM as well as the lack of standardized treatment due to the relative paucity of clinical trials addressing treatment of CM. A diagnosis of CM is achieved by a clinically relevant history and examination, CSF analysis that includes cytology, and neuroimaging consistent with radiographic CM. Treatment following staging of CNS disease (neuraxis imaging and radio-isotope CSF flow study) in appropriate patients (defined as limited extent of disease and reflected in a high performance status) includes systemic chemotherapy for radiographic bulky CSF disease, radiotherapy to sites of symptomatic disease, radiographic bulky disease or sites of CSF flow obstruction, and intra-CSF chemotherapy (primarily methotrexate, cytarabine, or thiotepa). Notwithstanding aggressive treatment, the majority of patients survive < 3 months suggesting patient selection for treatment is critical as is the need for clinical trials utilizing novel therapies.