A ternary flame system is presented that allows observations of soot oxidation in a hydrogen diffusion flame. A soot column is generated with a sooting acetylene/air coflowing laminar diffusion flame on an 11.1 mm burner. The column passes through a ring burner, which supports a hydrogen diffusion flame. The hydrogen flame produces a hot region where the soot is oxidized, producing a soot flame. The soot flame is steady for the first 60 mm above the ring burner, providing a region to observe soot oxidation. This experiment was designed to examine soot oxidation kinetics in regions far separated from soot formation, i.e., in a hydrocarbon-free flame. Temperatures were measured using ratio pyrometry at 450, 650, and 900 nm and deconvolution. Soot volume fractions were measured using laser extinction at 632.8 nm and deconvolution. Velocities were measured using high-speed imaging and flow visualization. Primary particle diameters were measured using thermophoretic sampling and transmission electron microscopy. Measured soot flux decreases with height, indicating soot oxidation. The soot oxidation rate was found to be between 0 – 0.8 g/m2-s.