The use of degenerate four-wave mixing in athree-dimensional, forward four-wave mixing geometry for two-dimensional imaging of combustion species is reported. In this configuration, abeam of circular cross section intersects in the flame the crossing area of two beams that have been focused to form thin sheets of light. The generated signal beam propagates in the direction that fulfills the phase matching condition and, therefore, is spatially separated from the other beams. The thin intersection volume of the three beams is imaged onto adetector. Thus, information on the signal distribution in one plane in the sample can be recorded. The method is demonstrated with experiments performed onOH molecules in apremixed acetylene-oxygen flame.