The excitable behaviour of neurons is determined by the activity of their endogenous membrane ion channels. Since muscarinic receptors are not themselves ion channels, the acute effects of muscarinic receptor stimulation on neuronal function are governed by the effects of the receptors on these endogenous neuronal ion channels. This review considers some principles and factors determining the interaction between subtypes and classes of muscarinic receptors with neuronal ion channels, and summarizes the effects of muscarinic receptor stimulation on a number of different channels, the mechanisms of receptor – channel transduction and their direct consequences for neuronal activity. Ion channels considered include potassium channels (voltage-gated, inward rectifier and calcium activated), voltage-gated calcium channels, cation channels and chloride channels. This article is part of the Special Issue entitled ‘Neuropharmacology on Muscarinic Receptors’. •Activation of muscarinic receptors (MRs) modifies neuronal signalling by altering the activity of membrane ion channels.•The principles governing MR-channel interaction are illustrated with reference to regulation of Kv7 and Kirchannels.•Effects of stimulating Gq-coupled MRs on various K+Cl−, cation and Ca2+ channel are discussed.•Gi/Go-coupled MRs activate Kir potassium channels, inhibit CaV calcium channels and inhibit transmitter release.•The topographical relation between MRs and channels and possible macromolecular channel-receptor complexes are discussed.