Many drugs used for induction or maintenance of anaesthesia provide a degree of skeletal muscle relaxation, but in general this is only mild to moderate at a surgical plane of anaesthesia. This chapter looks at different ways to achieve more profound muscle relaxation, neuromuscular blocking agents (NMBAs) and their mechanism, monitoring the neuromuscular junction, clinical assessment of recovery from neuromuscular blockade, monitoring adequacy of anaesthesia, individual agents, interactions with other drugs, and more.