During kidney development, branching morphogenesis occurs in the ureteric bud epithelial tube. Here, using time-lapse microscopy in mouse kidneys, the authors observe that this involves a unique behaviour of dividing cells in the branching bud that they term 'mitosis-associated cell dispersal'. Specifically, they see that many cells delaminate into the lumen before division and that the daughter cell then reinserts into the original site of the epithelium by virtue of a thin basal process that it inherits. The other cell, by contrast, reinserts at varying positions (1–3 cell diameters away), and this contributes to cell rearrangements during development of this tissue. Thus, cell division does not seem to be restricted to the epithelial plane during bud morphogenesis.