Oscillatory activity is proposed to be important in cerebellar information processing. Cerebellar oscillations, of unknown origin, have been reported in the granule cell layer of awake rats (6-8 Hz, Hartmann & Bower, 1998) and primates (13-25 Hz, Courtemanche et al. 2002). It has been proposed that the Golgi cell-granule cell feedback loop generates oscillatory activity (Maex & De Schutter, 1998). We previously described the responses of Golgi cells to somatosensory stimuli in urethane-anaesthetised rats and showed that they do not respond with oscillatory firing (Holtzman et al., 2003). During these experiments we did find another class of neurone that discharges in an oscillatory way.The experiments were done in adult rats, under urethane anaesthesia (1000 mg/ kg, i.p.), which were killed by overdose at the end of the experiment. We observed the spikes of a class of large granular layer neuron with firing characteristics unlike those of Golgi cells. The spontaneous spikes of these cells had similar mean frequencies to Golgi cells but were continuous and extremely regular, giving interspike interval histograms that were approximately symmetrical and very narrow in comparison to Golgi cells. Individual neurons expressed preferred firing frequencies in the range of 6-20 Hz. Electrical stimulation of peripheral afferents, from bilateral face, fore- and hindlimbs, produced a brief silencing of the spike discharges (duration 20-40 ms), after which spiking resumed. However, when spiking resumed, spikes occurred at preferred times related to the periodicity of the spontaneous firing. This oscillatory discharge lasted for 400-1900 ms, visible as peaks in a poststimulus time histogram, before desynchronising. These neurons were highly sensitive to the frequency content of a train of stimuli, falling silent at input frequencies >30 Hz. For input frequencies <30 Hz, the response was oscillatory but was frequency locked to the stimulus frequency, reverting to the preferred firing frequency after the stimulus train. Based on several lines of evidence, we suggest that these neurons may be Lugaro cells. They are large neurones located in the granule cell layer. These neurones fire as “oscillators with a preferred frequency” (5-15 Hz) in vitro (Dieudonne & Dumoulin, 2000) and inhibit Golgi cells. Our sample of putative Lugaro cells share broad peripheral receptive fields with Golgi cells, and we will provide evidence that the temporal dynamics of their oscillatory firing patterns may be suited to provide inhibition of Golgi cells.