Bagasse is the principal source of heat for the production of raw sugar. Early furnace designs were satisfactory from the standpoint of operation and steam output during the period when labor was plentiful and this by-product fuel was assigned little or no value. Rising costs of fuel, equipment, repairs, and wages, however, have altered this picture materially. Older plants consisted in a multiplicity of small boilers with refractory hearth-type furnaces. Operating efficiency was low, and steam output dropped during long periodic hearth-cleaning periods. These designs are definitely outmoded through the rapid advances which have been made during the past 10 years. Newer designs of steam-generating units now incorporate spreader stokers, water-cooled furnaces, bent-tube boilers, superheaters, air heaters, and bagacillo-return systems. They have more flexibility, greater capacity, higher efficiency, and are less subject to operational interruption. Many units of this type have now been in operation for considerable periods of time in practically all of the world’s raw-sugar-producing areas. It is the purpose of this paper to discuss, primarily, the operating characteristics of this new design as experienced with installations in Mexico. Comparative data also will be presented to stress normal operating differences between hearth-type and spreader-fired unit.