Background: People living with HIV are more ~usceptible for TB infection because HIV weakens the immune system. TB is the leading cause of death for those infected with HIV and is implicated in up to one-half of all AIDS deaths. Uptake of lsoniazid Prevention Therapy among people living with HIV is a proven, internationally recommended strategy to reduce TB burden among people live with HIV that has been effectively implemented in low resource settings. Despite the considerable benefits of implementing lsoniazid Prevention Therapy to reduce TB among people live with HIV, HIV programs have been slow to implement this TB­ reducing service. Particularly in this study area there is no research based information about knowledge and uptake of lsoniazid Prevention Therapy among people living with HIV. Objective: - This study designed to assess knowledge and uptake of lsoniazid Preventive Therapy and associated factors among people living with HIV in Bahir Dar town. Methods: - Institution based Cross-sectional study was conducted from February to March 2014 in Bahir Dar public health facilities. A 383 people live with HIV at four public health institutions that started ART services was selected by systematic random sampling. The study was conducted from February to March 2014. The findings were analyzed using SPSS version 20. Results: - Among people live with HIV 62.1 % had insufficient level of knowledge about lsoniazid Prevention Therapy. The proportion of people live with HIV who had uptake of IPT was 30.5%. Uptake of lsoniazid Prevention Therapy was statistically associated with sex of study participants [AOR=2.45, 95% Cl: 1.42, 4.25], duration on HAART [AOR=2.45 95% Cl: 1.29, 4.63], explanation given by health professionals about benefit of lsoniazid Prevention Therapy [AOR=5.51, 95% Cl: 3.28, 9.27] and educational status (primary, secondary and post­ secondary [AOR=3.87, 95% Cl: 1.47, 10.12], [AOR=5.77, 95% Cl: 2.50, 13.30] and [AOR=6.45, 95% Cl: 2.45, 15.79] respectively). Conclusion: - This study revealed that high number of study participants had insufficient level of knowledge about lsoniazid Prevention Therapy and low uptake of lsoniazid Prevention Therapy in the town. The finding suggests that the need to strengthen and integrate lsoniazid Prevention Therapy service with ART services. And there is need of promotion on uptake of lsoniazid Prevention Therapy in public health facilities. Key words: - HIV/AIDS, lsoniazid Prevention Therapy, PLHIV,