ObjectiveTo analyze adherence to treatment of tuberculosis infection and to identify risk factors for its compliance. DesignAn observational historical cohort study. SettingHospital Universitari Sant Joan d’Alacant (Alicante). ParticipantsAll patients with a tuberculin skin test (TST) done during tuberculosis contact tracing during 6 years. ResultsWe included 764 tuberculosis contacts in the analysis. 59.7% of the 566 patients who completed the contact tracing, had tuberculosis infection (TI). Of the patients with TI, 45.6% had not started treatment for tuberculosis infection (TTBI). Factors associated with not starting TTBI were: age (36-65 years, RR: 5.8; 95% CI: 1.2-27.5, and > 65 years, RR: 11.3; 95% CI: 2.0-64.0), the social relationship with TB case (RR: 2.2; 95% CI 1.2-3.8), and the TST reaction (≥ 15mm; RR: 0.5; 95% CI: 0.3-0.9). The completion rate for TTBI was 80.4% among people who started therapy. The treatment regimen was associated with greater compliance to TTBT (7-9H, RR: 12.7; 95% CI: 1.5-107.3). ConclusionsThe treatment compliance rate of Tuberculosis infection was high among people who started therapy. Almost a half of the contacts with TI did not start treatment, and associated factors were: age, social relationship, and the TST reaction. The treatment regimen was associated with greater compliance. It is important to know the factors associated with adherence to treatment of TI in each health area, and focus efforts on risk groups; thereby approaching the global control of tuberculosis.