This descriptive cross-sectional study collected data of the prevalence of diabetes mellitus (DM) among tuberculosis (TB) at the Urban DOTS (Directly observed treatment, short-course) Centers in the Kathmandu, Bhaktapur, and Lalitpur districts of Nepal. The prevalence of DM was assessed in 67 previously treated TB cases (PTTB) and 214 new TB cases. DM was diagnosed in 8 PTTB and 20 new TB patients. Clinical interviews identified 14 cases of DM, the rapid blood glucose test diagnosed 4 cases, and the oral glucose tolerance test (OGTT) diagnosed 4 cases. Impaired glucose tolerance and impaired fasting glycemia were found in 8 and 5 cases, respectively. The 18-24 age group had the largest number of new TB cases (82; 38.3%). However, the comorbidity of DM and TB was higher in the 35 years and older age group and was found in 24.2% of PTTB and in 23.1% of new TB cases. To provide the evidence of impacts of DM screening for TB cases, larger number of samples should be analyzed. The DM screening for TB patients is expected to start in developing countries. It should be initiated by clinical interview about DM and glucose tests by rapid kits.