A recent development in the water and sanitation sector is the concept of ecological sanitation (Eco-sanitation, or "Eco-San"); that is, the on-site storage and treatment of human fecal waste. The goal of this type of sanitation is to provide the user with a hygienic means of waste disposal, as well as a safe, stable, and useful end product. This paper examines the efficacy of such systems; namely, the type of treatment provided and the extent of pathogen destruction. Mathematical models of pathogen die-off data from experimental studies are used to estimate the hygienic quality of human fecal material under conditions normally found in Eco-San systems. A review of the literature shows major gaps in the data available to model the Eco-San systems. Lack of field data on the Eco-San process results in an incomplete description of the operating conditions. The scarcity of data on the kinetics of pathogen destruction at low temperatures also adds uncertainty to the assessment. Also, much of the available kinetic data is from studies that are carried out under conditions not necessarily encountered in Eco-San. Extrapolation of pathogen destruction from the kinetic models developed under different test conditions show inconsistent results. The use of the EPA Part503 Biosolids Rule pathogen reduction model also is not appropriate as a guide to determining treatment efficiency. More research and data on the survival of pathogens at lower temperature ranges is needed to determine the exact nature of Eco-San process efficiency. Existing data is used to develop a simplified model for the prediction of pathogen destruction. Recommendations are made to develop indicators of the efficacy of Eco-San treatment. The conclusions include a discussion on the way to operate double-vault latrines in dual phase manner that will result in a safe, hygienic end product.