The present study reports an updated detailed chemical kinetic model for soot formation. The model combines recent developments in gas-phase reactions, aromatic chemistry, soot particle coagulation, soot particle aggregation, and develops a new submodel for soot surface growth. The model was tested against experimental profiles of major and minor chemical species, aromatics, soot volume fractions, and soot particle diameters reported in the literature for nine laminar premixed flames of ethane, ethylene, and acetylene. The numerical agreement between the model predictions and experimental data is generally within a factor of 3. This level of agreement is very encouraging, considering the current uncertainties in the thermodynamics and kinetics of aromatics and soot chemistry. The principal accomplishment of the present study is that the demonstrated level of agreement all around-main flame environment, aromatics, and soot-can be attained with a single reaction model. (C) 2000 by The Combustion Institute.