Abstract A consortium of Ethiopian and American physicians and public health experts propose implementing and studying a program of active screening for pulmonary tuberculosis (PTB), HIV, and syphilis in an Ethiopian Prison. In a pilot study at Kaliti Prison, we compared prevalence rates between entrants being admitted and long-term residents of the prison. The higher rates in residents compared to entrants for PTB symptoms (1.4 vs. 22.3%) and HIV (3.6 vs. 15.2%) suggest that transmission of both diseases is occurring in this prison. Because early detection and treatment could reduce transmission of both of these infections, we propose to screen entrants continuously and the resident population twice 12 months apart over a period of 18 months. PTB screening will consist of questions about symptoms with further evaluation to include sputum microscopy, culture and chest x-rays. HIV and syphilis serological screening will be performed in the prison by HIV rapid tests and RPR. Prisoners will be isolated during evaluation and initial treatment to reduce risk of transmission, treated according to Ethiopian national guidelines and tracked for responses to their therapy. For our operational research objectives, we will assess the program for its logistics, effectiveness and costs and for the barriers to its implementation and to participation by prisoners. We will also compare the contributions of various diagnostic modalities for PTB (symptoms, microscopy, cultures with drug susceptibility testing, and chest x-rays). For our epidemiological objectives, we will measure the baseline prevalence rates of PTB (including drug-resistant TB), HIV and syphilis in the prison population and compare rates in entrants versus long-term resident inmates. We hypothesize that these 3 diseases are transmitted within the prison and will seek further evidence for this by searching for spatial clustering of TB cases between and within prison zones. Finally as a clinical objective, we will compare the clinical presentations and treatment outcomes of prisoners diagnosed by active screening to those detected by the currently-practiced, passive (self- referral) methods for detecting TB.