The possible use of peat/coal blends in utility boilers was studied. From fuel and ash properties estimates were made of the changes from coal firing practice that would be required in boiler design and fuel preparation. Boiler fouling, slagging and efficiency effects were predicted and compared with behavior of plants operating on coal or peat alone. It is expected that blends containing 50 percent peat would require relatively minor design changes from coal firing practice, but the firing of peat alone calls for substantially different design approaches.