The ability to perform clinical skills competently and safely is a big part of being a doctor and as such the General Medical Council (GMC) in its 'Tomorrow's Doctors' document, stresses the importance of acquiring sound clinical skills. Lumbar punctures (LPs) are often considered to be one of the more technically difficult of these clinical skills to perform. This is because performing LPs requires sound anatomical knowledge, safe administration of local anaesthetic and the ability to establish and maintain a sterile field. LPs are used in a wide range of specialties and may be done for diagnostic or therapeutic purposes. Diagnostic LPs include cerebrospinal fluid (CSF) analysis for infection or blood metabolites, whilst therapeutic LPs may be done for example to administer spinal anaesthetic and intra-thecal chemotherapy or to relieve pressure in patients with communicating hydrocephalus. In this article we provide a stepwise overview on how to safely perform an LP.