The treatment of municipal sewage at publicly owned treatment works (POTWs) leads to the production of considerable amounts of residual solid material known as sewage sludge, which is widely used in agriculture and land reclamation. Elevated levels of naturally-occurring and man-made radionuclides have been found in sludge samples, suggesting the possible radiation exposure of POTW workers and members of the public. The Interagency Steering Committee on Radiation Standards (ISCORS) therefore conducted a limited survey of radioactivity in sludge across the United States. Concurrently, to assess the levels of the associated doses to people, it undertook to model the transport of the relevant radionuclides from sludge into the local environment. The modeling work consisted of two steps: First, seven general scenarios were constructed to represent typical situations in which members of the public or POTW workers may be exposed to sludge. Then, the RESRAD multi-pathway environmental transport model generated sludge concentration-to-dose conversion factors. This report describes the results of this dose modeling effort, and provides a complete description and justification of the dose assessment methodology.