Background: Competency assessment has a key role in the assurance of quality professionals in every discipline. Competency assessment is a method by which we can verify that our employees are competent to perform tasks timely. To derive the greatest benefit from the application of competency assessment in the health professionals, we must be sure that we are addressing areas where our efforts are utilized to optimize the patient care. There is no research done on the competency assessment so far except the report send by Technical Vocational and Educational Training. Objectives: To assess knowledge, attitude and practice of health professionals towards competency assessment and factors were associated with competencies at Debre Birhan Health Science College, 2013. Methods: A facility based cross sectional study was conducted using interview technique. Study participants were all students taking competency assessment in all departments at Debre Berhan Health Science College in two rounds. The percentage of participants who were competent was computed. Factors associated with competency were assessed using bivariate and multivariable logistic regression. Results: Among the total participants (n = 287), (57.8 percent) were female. Among the (n = 287) study participants, 226 (78.7%) were competent. Of these, 88.5% of the candidates were learned at governmental institution. Predictors of competency were department of the respondent AOR [95%]; 0.05 [0.01, 0.45], expectation of the results [AOR (95% CI) = 0.13 (0.02, 0.85)], number of competency taken [AOR (95% CI) = 0.11 (0.01, 0.88)] and candidates’ knowledge of their right and obligations AOR [95%]; 3.7 [1.3, 10.3]. Conclusions: Significant numbers of candidates were not yet competent due to various factors at different level. Therefore, comprehensive work should be done on the instructors, students and the center to make the candidates competent.