A soot formation and oxidation model is presented for laminar axisymmetric non-premixed flames using a mixture fraction based combustion model, which is appropriate for fires where the detailed chemistry of the fuels is unknown. This model relies on an analytical description of soot processes in the centreline of the flame guided by flow similarity relationships established from global experimental data in smoke point laminar flames. The selection of the model parameters is based on numerical calibrations by comparison with detailed temperature and soot concentrations in laminar candle type flames. Application to any fuel is made by accounting only for the sooting tendency employing the laminar smoke point height of the fuel. It is shown that the soot formation and oxidation model gives satisfactory results and a good phenomenological explanation of the influence of soot processes on the structure of the flame. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.