Several lines of evidence suggest that α-bungarotoxin-sensitive neuronal nicotinic acetylcholine receptors may play a developmental role by modulating plasticity in neuronal circuits. The α7 subunit, a main component of these receptors, is expressed in most regions of the brain, including the cerebellum, where it is present almost exclusively in Purkinje cells and deep cerebellar nuclei. Purkinje cells constitute the only efferent pathway of the cerebellum and their development involves complex interactions, which have been extensively studied. They therefore provide a potentially useful model for analysis of developmental plasticity which could be influenced by α7 neuronal nicotinic receptors. In the present study a previously characterized monoclonal antibody (mAb 307) has been used to determine the temporal pattern of expression of the α7 subunit in the developing rat cerebellum. No detectable α7 immunoreactivity is found between P0 and P2. Between P3 and P5, however, the Purkinje cell layer shows moderate immunolabeling. α7 expression in this layer increases rapidly between P8 and P15. This increase in α7 staining, which overlaps in time with important developmental and synaptogenic events, is not uniform throughout the cerebellar cortex. Thus, between P3 and P5 all Purkinje cells are weakly labeled, while at later stages (P8–P15) immunolabeling becomes more intense but, at the same time, disappears from Purkinje cells in rostral lobules. In addition, a very well defined pattern of discontinuous or columnar labeling is detected in regions of the Purkinje cell layer where α7 subunits are being expressed. Finally, at P20, α7 subunit labeling is found again in all Purkinje cells, although with lower intensity. These results suggest that α7 receptor expression is developmentally regulated, with a time course that parallels the final differentiation of Purkinje cells. In addition, the heterogeneous spatial distribution of α7-containing nicotinic receptors indicates that, during cerebellar maturation, these cells may receive different signals that modulate receptor gene expression in a very specific way.