This paper presents an exptl. study of a direct-flame type solid oxide fuel cell (DFFC). The operation principle of this system is based on the combination of a combustion flame with a solid oxide fuel cell in a simple, no-chamber setup. The flame front serves as fuel reformer located a few millimeters from the anode surface while at the same time providing the heat required for solid oxide fuel cell operation. Expts. were performed using 13-mm-diam. planar solid oxide fuel cells with Ni-based anode, samaria-doped ceria electrolyte and cobaltite cathode. At the anode, a 45-mm-diam. flat-flame burner provided radially homogeneous methane/air, propane/air, and butane/air rich premixed flames. The cell performance reaches power densities of up to 120 mW/cm2, varying systematically with flame conditions. It shows a strong dependence on cell temp. From thermodn. calcns., both H2 and CO were identified as species that are available as fuel for the solid oxide fuel cell. The results demonstrate the potential of this system for fuel-flexible power generation using a simple setup.