Lumbar puncture (LP) is a useful diagnostic tool in a wide spectrum of paediatric clinical situations. A common indication is to rule out a serious intracranial infection in a febrile child. Success rate can be optimised by proper positioning, appropriate technique and enhanced operator's skill in performing the procedure. The purpose of this review is to explore the indications and contraindications for performing paediatric LP, to describe the anatomical and physiological knowledge required to maximise success rates and to describe complications and their management. We will also provide advice on requesting various cerebrospinal fluid studies, interpretation of results and clinical situations in which LP may be indicated.