Background; employingstandard precautions means taking precautions with everybody. If precautions are taken with everyone, health care workers do not have to make assumptions about people's lifestyles and risk of infection. Objectives: The main objective of the study is to assess the knowledge, attitude and practices of medical students on Standard precautions. Methods: This cross sectional health institution based survey was conducted in TASH, Addis Ababa University,among medical students who are 4th, 5th and 6th year. The study uses quantitative methods. Statistical significance was determined by computing mean variations using logistic regression. Result:The total knowledge score showed the level that 118(54.6%) had fair knowledge 71(32.9%) has good knowledge and 27(12.5%) had poor knowledge. Total knowledge score of respondents range from 6 to 18 out of 18 the mean knowledge score 13.37 with sd of+2.42.The knowledge level on standard precaution132 (61.1%) had good knowledge, 25(11.6%) fair and 59(29.6%) poor knowledge.Attitude score of the respondents showed that 180(83%) scored above half. Overall practice score showed that 117(53.9%) had fair practice while 15(6.9%) had good practice and 85(39.2%) had poor practice. Practice score standard precaution showed that 125(56.8%) had fair 69(32.6%) poor and 23(10.6%) good practice. Hand hygiene practice showed that 12.9% had good practice while 21% fair and 66.1% poor practice.Weak association was found between knowledge and attitude (r = 0.354; P<0.001); knowledge and practice to UP standards (r=0.201; P<0,001); attitude and practice towards UP (r=0.425; P<0.001). Conclusion: Medical students had a better Knowledge and acceptable level of attitude towards standard precaution but Medical students had poor knowledge and practice towards hand hygiene, overall they had poor practice to all components Strengthen and integrate standard precaution with the routine services through providing training for medical students in the Hospitals and health centers they are attached. Keywords: standard precaution, medical students, standard precaution related