M. tuberculosis is a possible cause of uveitis; the diagnosis is often difficult. The aim of this study is to evaluate, in this context, the application of an interferon gamma assay, the SpotTB™. The prospective study, in patients presenting with uveitis without obvious cause and not resolving with local treatment, compared the therapeutic approach (giving antituberculous treatment or not) with and without the result of the SpotTB™. The analyses included 23 patients: 78% had received BCG; 78% had isolated ocular involvement; 22% had associated mediastinal lymphadenopathy. The results of the IDR and the SpotTB™ were concordant in 61%, discordant in 22% and non-evaluable in 17% of cases. In the patients with isolated ocular involvement the SpotTB™ avoided treatment in five and reinforced the decision not to treat in 13 others. In the patients with mediastinal lymphadenopathy, the SpotTB™ reinforced the diagnosis of sarcoidosis in four cases (one lost from view). In conclusion, when infection with M. tuberculosis is considered in the aetiology of uveitis the SpotTB™ allows, in a significant number of cases, the avoidance of antituberculous treatment.