SETTING—Itaboraí Municipality in Rio de Janeiro, Brazil. OBJECTIVE—To evaluate access to tuberculosis (TB) diagnosis for users of the Family Health Program (FHP) and Reference Ambulatory Units (RAUs). DESIGN—A cross-sectional study was conducted in Itaboraí City, Rio de Janeiro, Brazil. Between July and October 2007, a sample of 100 TB patients registered consecutively with the TB Control Program was interviewed using the primary care assessment tool. The two highest scores, describing ‘almost always’ and ‘always’, or ‘good’ and ‘very good’, were used as a cut-off point to define high quality access to diagnosis. RESULTS—FHP patients were older and had less education than RAU interviewees. Sex and overcrowding did not differ in the two groups. Patient groups did not differ with regard to the number of times care was sought at a unit, transport problems, cost of attending units and availability of consultation within 24 h. Adequate access to diagnosis was identified by 62% of the FHP patients and 53% of the RAU patients (P = 0.01). CONCLUSION—In Itaboraí, Rio de Janeiro, TB patients believe that the FHP units provide greater access to TB diagnosis than RAUs. These findings will be used by the Department of Health to improve access to diagnosis in Itaboraí.