There are achievements obtained from the implementation of occupational competencyrnassessment and certification system in Technical-Vocational Education and Training (TVET,)rnincluding improvements in quality and relevance of TVET provision. The implementation inrnEthiopia in general and specifically in Addis Ababa city administration has faced with manyrnchallenges with different nature. This research study aimed at investigating the practices andrnchallenges in the occupational competency assessment and certification systemrnimplementation in TVET in Addis Ababa city administration. The study used a mixedrnresearch design, employing both quantitative and qualitative data. The sample populationrntaken for this study were 20 management members at Federal TVET Agency and AddisrnAbaba City Administration Competency Assurance Agency, 140 regular trainees from levelrn1-5, 30 MSME operators, 50 industry workers, 140 short term trainees in manufacturingrnsector, 20 assessors, 20 supervisors, and 20 trainers, a total of 470. Purposive sampling,rnexpert sampling, quota sampling and simple random sampling techniques have been used.rnThe data has been collected using questionnaires, interviews, focus group discussions andrnsecondary sources such as reports, broacher, and policy documents. Frequency distribution,rnpercentage and mode are statistical measures mainly used and correlation and casualrnanalysis approaches were utilized to analyze the quantitative data. The qualitative datarnobtained through interview, focus group discussion were analyzed using qualitative analysisrnmainly deductive, inductive and interpretative analysis methods. The finding revealed that thernextent of deviation of practice of occupational competency assessment and certification fromrnthe standard procedure and principles was beyond acceptable level. Incompetent andrnunethical assessors, poor quality assessment centers, rent seeking practices and interferencernof training regulator are some among major challenges. Weak leading and implementingrncapacity of the federal and city administration of occupational competency assessment andrncertification body is fertile ground for the challenges to be muscular. The incapability of thernleading and implementing body is basically manifested by inability to implement the systemrnas per the standard procedures and principles. Lack of quality in occupational standards andrnassessment tools is because of unable to mobilize industry and create ownership. Practicesrnout of standard procedures in developing and engaging assessors and assessment centers arernindications for the incapability of proper implementations. Backward handling method ofrnassessment tools and certification process has resulted in poor security and inefficient servicernwhich has laid good foundation for rent seeking practices and lack of good governance. Thernchallenges encountering the implementation of occupational competency assessment andrncertification could be mitigated through enhancing the leading and implementing capacity ofrnthe federal and city administration bodies. This could happen through restructuring ofrncurrent disabled and poorly staffed structure and keep continuous capacity building andrnimprovement. Utilizing technologies in the entire process, from registration to therncertification, is also part of sustainable solutions for the challenges.