Background : Tuberculosis along with HIV is a major cause of death worldwide. Globally in2014, there were an estimated 9.6 million people get TB. Achievement conversion rate of TBin the province of Lampung based Riskesdas 2010 and 2013 experienced a sharp decline of90% in 2011 to only 38.1% in 2014 (National target> 85%). Internal and external factors are closely related to the incident, it is necessary to do in-depth study to determine the factors that influence the conversion failure of TB patients in the intensive phase of treatment.Methods : This research was analytic observational cohort design. The study population was patients with pulmonary tuberculosis in the city of Bandar Lampung starting treatment. The total sample of 126, the dependent variable was the incidence of failed conversion, independent variables are internal factors (positive gradation, BMI, hemoglobin levels and symptoms of anxiety of patients) and external factors (smoking, alcohol consumption and the role of health workers). Samples were obtained by exhaustive sampling.Results : AFB positive gradation (aRR=12,7; 95%CI: 3,580 to 45,539; p=0,000), the role ofhealth workers (aRR=9,8; 95%CI : 3,451 to 28,221; p=0,000) and consumption of alcoholic beverages (aRR=5,5; 95%CI : 1,927 to 15,566; p=0,001) proved to be a risk factor for conversion failure with probability event together amounted to 95.3%.Conclusion : The risk factors that affect the incidence of TB is conversion failure patients with 2+ and 3+ BTA gradation, alcohol consumption and the role of health workers.