BACKGROUND: Children are highly susceptible to Mycobacterium tuberculosis infection, and about 70% of children living in the same households with pulmonary tuberculosis-positive patients will become infected. However, pulmonary positive tuberculosis is a common phenomenon and the implementation of the recommended contact screening and initiation of isoniazid preventive therapy is very low. Therefore, this study is aimed at assessing contact screening practice and initiation of isoniazid preventive therapy of under-five children among pulmonary tuberculosis-positive patients in Bahir Dar, northwest Ethiopia. METHODS: A facility-based cross-sectional study was conducted from March 1 to 30, 2016. A total of 267 pulmonary tuberculosis-positive patients were included in this study. To identify independent predictors of contact screening and isoniazid preventive therapy initiation, we performed multivariable logistic regression analyses using SPSS version 20 with CI of 95% at p value < 0.05. RESULTS: A total of 230 (90.2%) pulmonary tuberculosis-positive patients had single contacts with their under-five children. One hundred nine (64.8%) children were screened. From those screened, 11 (7.4%) developed tuberculosis disease and started antituberculosis treatment. Forty-four (31.9%) children started isoniazid preventive therapy. Sex of the participants, place of service delivery, relationship with contacts, HIV status, and attitude of PTB+ cases were significant predictors of contact screening (p < .05). Participant's knowledge, attitude of participants, and relationship of the child with participant were significant predictors of isoniazid preventive therapy initiation (p < 0.05). CONCLUSION: Contact screening practice and isoniazid preventive therapy initiation of children under the age of 5 in Bahir Dar zone were very low. Intimate family contact with pulmonary tuberculosis-positive patients, place of service delivery, and attitude towards screening are the key factors of contact screening. Participant's knowledge, attitude of participants, and relationship of the child with participant are the key factors of isoniazid preventive therapy initiation. Therefore, household contact screening and isoniazid preventive therapy initiation should be paid attention to reduce transmission.