Although the cholinergic modulation of the cochlear nucleus (CN) is important, neither its cellular consequences, nor the types of receptors conveying it are precisely known. The aim of this work was to characterise the cholinergic effects on morphologically identified giant cells of the CN, using electrophysiology, Q-PCR and immunohistochemistry. In vitro experiments were conducted on thin slice preparations from the brainstem of 10-14-day-old Wistar rats. The protocol was authorised by the Committee of Animal Research of the University of Debrecen, and it was in accordance with the appropriate international and Hungarian laws. Application of the cholinergic agonist carbachol increased the spontaneous activity of the giant cells (from 2.4 ± 0.5 Hz to 7.3 ± 1.3 Hz; avg ± SEM; n = 36). The increased activity was partly the consequence of the reduction of a K+ conductance, and this effect was mediated via M4 and M3 receptors. Cholinergic modulation affected the synaptic transmission targeting the giant cells, too. Excitatory synaptic currents evoked by the stimulation of the superficial and deep regions of the CN were sensitive to cholinergic modulation: the amplitude of the first postsynaptic current was reduced, and the otherwise present short-term depression was also affected (from 45 ± 10 pA to 32 ± 12 pA; the paired pulse ratio (PPR) changed from 0.72 ± 0.09 to 1.02 ± 0.05; n = 8). These changes were mediated via M3 receptors alone and via the combination of M4, M2, and M3 receptors, when the superficial and deep layers were activated, respectively. Inhibitory synaptic currents evoked from the superficial layer showed prominent short-term depression (PPR = 0.5 ± 0.1; n = 8), but they were unaffected by carbachol. In contrast, inhibitory currents triggered by the activation of the deep parts exhibited no significant short-term depression (PPR = 0.93 ± 0.1; n = 7), but they were highly sensitive to cholinergic activation, which was mediated via M3 receptors (the amplitude of the first peak decreased from 119 ± 34 pA to 33 ± 13 pA; n = 7). Our results indicate that pre- and postsynaptically expressed muscarinic receptors have important roles in mediating the effects of cholinergic modulation of the CN, and they strongly influence the excitability and firing characteristics of the giant cells.