The improper management of hospitals and other health care facilities waste causes serious environmental problems in terms of air, water and land pollution. There are potential risks to environment and human health from improper handling of health care facilities wastes. This study was focussed on the microbial indicators and pathogen reduction capacity of the compact onsite wastewater treatment practice in Urban Health Care Facilities (HCFs) and its potential public health benefits at MCM hospital in Addis Ababa. The study was conducted by using experimental quantitative method for the analysis of wastewater to estimate the bacterial indicators and pathogenic composition along with transect walk or participatory observation. Samples of waste water were taken from the onsite WWTP influent and effluent and then measured for indicator and pathogenic bacteria concentration using APHA method and compared with a standard of quality on Java Governor No 61 of 1999. The bacteriological, indicators and other pathogenic qualities of hospital wastewater discharged into the environment from MCM hospital was investigated to assess the public health burden reduction efficiency of onsite wastewater treatment plant (WWTP) practice at MCM hospital and its potential public health. The bacteriological parameters were carried out using the standard microbiological techniques those examined were total heterotrophic bacterial counts called most probable number (MPN) and the standard plate count (CFU) techniques. The result of this study revealed that the practice of onsite wastewater treatment at MCM has reduced the mean of heterotrophic plate count by 76.34%, Staphylococcal count by 99.68% , total coliform count by 99.89%, faecal coliform counts by 99.88%, E. coli count by 99.55% and Enterococcal counts and 99.71%. The % reduction of pathogenic bacteria by this onsite wastewater treatment practice is Salmonella by 75 % Shigella 50% Staphylococcal count CFU/mL 99.68% E. coli count MPN/100ml 99.95% As a summary this result showed that the characteristic of the wastewater influent at MCM hospital containing contaminants that exceed the quality standard based on Java Governor No 61 of 1999. The pathogen reduction efficiency of onsite wastewater treatment plant (WWTP) practice at MCM hospital showed that microbiological parameters studied revealed that the hospital wastewaters though show few parameters whose values are higher than the WHO percept levels. Most falls within the WHO acceptable limits after the treatment. There is contamination of the receiving environment due to the discharged hospital wastewater in the absence of this treatment which could probably be hazardous to human health. The practice of onsite wastewater treatment at MCM has reduced the mean of all indicator bacteria by 94.83 % and the identified pathogenic bacteria by 82.25% this is a great deal of public health benefit to community and particularly to those who are dependent on the receiving water body for different socioeconomic activities.rnKeywords: Hospital wastewater, Pathogen reduction, Onsite Wastewater treatment infectious Wastewater, influent, effluent, WWTP, efficiency, Public health