Background: Sierra Leone started the Direct Observation Treatment Strategy (DOTS) for the treatment of pulmonary tuberculosis in 1992. The country’s pulmonary tuberculosis (PTB) treatment program is now standardized according to international scale. Under the national standardized PTB treatment system, the regimen for new PTB patients consists of a 2-month intensive treatment phase with isoniazid, rifampicin, pyrazinamide and ethambutol, followed by a 4-month continuation phase with rifampicin and isoniazid. Aims: To determine and analyse the annual PTB treatment success and incidence rates, treatment defaulters’ rate, and pulmonary tuberculosis mortality from 1992 to 2002 under the DOTS program at the Germany Leprosy Relief Association’s (GLRA) 13 regional diagnostic centers and chest clinics in Sierra Leone and to compare this data with the annual national tuberculosis data stored in WHO tuberculosis database covering the period 1992-2010. Study Design: The study retrospectively analysed pulmonary tuberculosis annual incidence rates for study subjects who registered for diagnosis and later for treatment at the GLRA 13 regional diagnostic centers and chest clinics from 1992 to 2002. From these data we were able to determine the treatment success and defaulters’ rates, and PTB mortality for these subjects. We also analysed data of the annual national tuberculosis incidence and success rates, and mortality rates retrieved from World Health Organisation (WHO) TB data for Sierra Leone for the period 1992-2010. Twenty six (26) healthcare service providers were also interviewed for additional information about the main cause of mortality and reasons for treatment defaults among pulmonary tuberculosis patients during the period under investigation. Study Subjects: A total of 2,958 (1,881 men and 1,077 females) mostly adults of age range 15-65 years were diagnosed and later treated for pulmonary tuberculosis from 1992 to 2002 at the various GLRA diagnostic and treatment centers in the country. Setting: The study was a multicenter study conducted at the Germany Leprosy Relief Association’s (GLRA) main referral diagnostic center and chest clinic at Lakka in Freetown and the Department of Environmental Health Sciences, Njala University in Bo, Sierra Leone. Pulmonary tuberculosis treatment outcomes data used in this study were obtained from TB patients who were admitted at various GLRA chest clinics in Sierra Leone from 1991-2002. Data analysis and literature reviews were done at the Department of Environmental Health Sciences, Njala University in Bo, Sierra Leone from 2011 to 2012. Results: The most important finding of this investigation was that the annual pulmonary tuberculosis incidence and treatment success rates (% cured rate and % completed treatment rate) rose significantly during the period under review for both the GLRA’s study subjects and the cases stored in the WHO tuberculosis database. Conclusion: The significantly high and growing number of annual PTB incidence rates during this HIV/AIDS epidemic reinforces the need for routine PTB treatment monitoring and supervision as well as compulsory HIV testing for tuberculosis patients seeking treatment.