The physical characteristics and composition of biomass can vary significantly from coal and from one fuel to another, and these differences can impact the structure of the resulting pulverized fuel flame, particularly the volatile flame. The length and location of the volatile flame, which is the zone dominated by the combustion of volatiles, is important not only to flame stability and length but also to the formation of pollutants such as NOx. In this work, the effects of biomass volatile fraction and particle size on the length of the volatile flame were investigated for cofired flames of pulverized coal and wood waste. The volatile flame length was measured experimentally in a 35 kW combustion facility via axial measurements of CO and CO2 made along the centerline. Numerical simulations were employed to aid the interpretation of the impacts of wood waste cofiring on the volatile flame. The length of the volatile flame zone was found to be sensitive to the location of volatile matter release and the amount of volatile matter released within the volatile flame zone. Large biomass particles, with high axial momentum and long heating times, break through the fuel-rich volatile flame zone, releasing volatiles downstream into an oxygen-rich environment. The delayed release of volatiles reduces the amount of volatile fuel in the fuel-rich region, leading to shorter volatile flames, which in turn augments breakthrough of particles before complete release of volatiles. On the basis of CO and CO2 concentration measurements, cofired flames with 20 wt % wood waste and 80 wt % coal were found to have 21% shorter volatile flames compared with coal-only flames. Numerical simulations verified that volatile reactions take place past the end of the volatile flame. To reduce the amount of particles that pass through the volatile flame before complete devolatilization, the wood waste particle size was reduced. The resulting volatile flame was 27% longer for the 20 wt % cofired case compared with coal-only volatile flames. Increased volatile matter content, characteristic of biomass fuels, leads to an increased volatile flame length when all of the volatiles are released in the near-burner region.