ABSTRACT: BACKGROUND: Tuberculosis remains one of the leading causes of morbidity and mortality in low-resource countries. One contagious patient can infect 10 to 20 contacts in these settings. Delays in diagnosing TB therefore contribute to the spread of the disease and sustain the epidemic. Objectives The aim of this study was to assess delays in diagnosing tuberculosis and the factors associated with these delays in the public hospitals in Moundou and Ndjamena, Chad. METHODS: A structured questionnaire was administered to 286 new tuberculosis patients to evaluate patient delay (time from the onset of symptoms to the first formal or informal care), health-care system delay (time from the first health care to tuberculosis treatment) and total delay (sum of the patient and system delays). Logistic regression was used to identify risk factors associated with long diagnostic delays (defined as greater than the median). RESULTS AND DISCUSSION: The median [interquartile range] patient delay, system delay and total delay were 15 [7-30], 36 [19-65] and 57.5 [33-95] days, respectively. Low economic status (aOR [adjusted odds ratio] =2.38 [1.08-5.25]), not being referred to a health service (aOR=1.75 [1.02- 3.02]) and a secondary level education (aOR=0.33 [0.12-0.92]) were associated with a long patient delay. Risk factors for a long system delay were a low level of education (aOR=4.71 [1.34-16.51]) and the belief that traditional medicine and informal care can cure TB (aOR=5.46 [2.37-12.60]). CONCLUSION: Targeted strengthening of the health-care system, including improving patient access, addressing deficiencies in health-related human resources, and improving laboratory networks and linkages as well as community mobilization will make for better outcomes in tuberculosis diagnosis.