Particulate emissions from a group of municipal sludge incinerators with multiple-hearth furnaces, one with a fluidized-bed furnace were characterized. Three plants operated at or near autogenous burning conditions. Chemical element composition was determined for total and sized emission samples by x-ray fluorescence analysis. Objectives of the investigation were to obtain specific elemental emission and to provide source inventories and source signatures, especially in terms of particle size to assist the development and evaluation of source apportionment models. Considerable enrichment of several elements (S, V, Cu, Zn, Cd, Sn and Pb) in the particulate emissions compared to their content in the sludge feed was observed. The largest average enrichment ratio were found with cadmium (31), zinc (13), lead (9), and sulfur (8).