This report presents a critical review of the literature from laboratory and full scale studies regarding density levels of indicator and pathogenic organisms in municipal wastewater sludges and septage. The effectiveness of conventional municipal sludge stabilization processes (mesophilic anaerobic and aerobic digestion, composting and lime stabilization) and dewatering processes (drying beds, lagooning/storage, and sludge conditioning/mechanical dewatering) was evaluated for reducing density levels of indicator and pathogenic organisms. To accomplish this objective, a comprehensive review was performed of all literature published on this topic between 1940 and 1980. An annotated bibliography presents all citations reviewed, with pertinent abstracts and methods used by researchers.