Cell-to-cell communication mediated by the evolutionary conserved Notch signalling pathway regulates cell fate decisions and patterning in various tissues in invertebrates and vertebrates (Science 284 (1999) 770). In mouse, four Notch receptors, five ligands of the delta and Serrate types, three fringe glycosyltransferases that modify Notch, and a growing number of direct transcriptional targets of Notch are known. Mutational analysis of Hes1 (Nat. Genet. 24 (2000) 36) and Math1 (Science 294 (2001) 2155) have implicated Notch signalling in the regulation of intestinal epithelium development and homeostasis. Here, we describe the expression of the genes encoding the murine Notch receptors (Notch1-4), the ligands (delta1, 3, 4 and Jagged1, 2), the modifying glycosyltransferases of the fringe family (Lfng, Mfng, Rfng) and four Hes genes (Hes1, 5, 6, 7) in the mouse small intestine during fetal (E13.5 and E18.5) and postnatal (P25) development. All analyzed Notch pathway components were expressed in the intestine, although at different levels and with varying spatial and temporal distribution, consistent with roles of Notch signalling at various stages of intestinal development and renewal.