Street vended foods are ready-to-eat foods and beverages. The consumption of these foods is common in Ethiopia. But, researches made in some countries show that street vended food are cause for different diseases and even death. This study was done to accesses the bacteriological contamination level of street vended foods and their associated factors that causes for safety problems in Bole and Yeka sub cities in Addis Ababa, Ethiopia. Community based Cross sectional study, survey with laboratory experiments study was used to undertake this research from April to June, 2021G.c. There were 5 vending sties and 236 street food venders were estimated by Bole and Yeka sub cities Trade and Small Scale Enterprise. Purposive sampling was used. 60 street food venders were interviewed to get socio-demographic profile, hygienic and sanitation practices of street food vendors. Samples were collected from each interviewed venders. 20 “ambasha”, 20 sambusa” and 20“pasty” were aseptically collected from Bole Dildyi, Megenagna, Lamberet, CMC and Summit. Data were analyzed using Microsoft Excel 2010, chi-square taste to investigate the relation between the bacterial contamination level and associated factors. Ethical clearance was done before data collection. The methodology of American health protection Agency was used to investigate S. aureus, salmonella and E. coli. The result of this study was interpreted by comparing with ISO (2010) microbial standards for ready to eat foods. The result of this study show that, 70 % of the street vended foods were contaminated with different bacterial species. 31.7% of the street foods were satisfactory while 25% of the street foods were border line and 26 % of the street foods were unsatisfactory for staphylococcus aureus. For salmonella taste, 78.3 % of the street foods were satisfactory while 21.7% were potentially hazardous. Eighty five percent of the street foods were satisfactory and 15% were unsatisfactory for E. coli. The presence of these bacteria in street foods could cause potential public health. So street foods in theses area were not safe for consumption. There was a relation between Educational level (p=0.0034), awareness of venders about food borne diseases (p=0.0034), covering of foods (p=0.011), sell left over foods (p=0.011) and street food contamination. Most of the venders have no any food safety training so concerned bodies should give emphasis for this informal business sectors.