The formation, dynamics and structure of cellular flames in circular non-premixed jets are examined with three-dimensional numerical simulations incorporating detailed descriptions of chemistry and transport. Similar to past experiments reported in the literature, CO2-diluted hydrogen in diluted or pure oxygen co-flowing streams in the proximity of the extinction limit are considered. As in the experiments, several preferred cellular states are found to co-exist with the particular state realized depending on initial conditions as well as on the jet characteristics. The Simulations provide additionally the temporal transitions to different stationary or rotating cellular flames, their detailed structure, and the dependence of the scaling of the realized number of cells with the vorticity, thickness. (c) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.