Combustion of biomass and municipal solid wastes is playing an increasingly important role in modern society as one of the alternative energy sources reducing global CO2 emission and minimizing land contamination. The combustion of these fuels, especially municipal solid waste is subject to high moisture variations, which could jeopardize the plant performance. In this paper, both the experimental results and details of mathematical simulation for the combustion of biomass and simulated wastes in a stationary bench-top rig are presented. Stable combustion was achieved for all moisture contents except the highest level tested (47%) where the flame extinguished 20 min after ignition. It was found that drier fuels undergo two distinctive combustion stages and the burning rate was inversely proportional to the moisture content. Wetter fuels had a thinner flame front and the combustion stoichiometry shifts from sub-stoichiometric (fuel rich) to super-stoichiometric (fuel lean) as the moisture content increases. Results show that 30% moisture in fuel produced the lowest flame-front temperature while 40% moisture in fuel resulted in the highest flame-front temperature. Flame extinction at high moisture level is related to the amount of combustible material above the moisture evaporation layer and it was found that the minimum combustible mass above the evaporation zone was 1.25 kg m(-2) for sustained burning under the conditions investigated.