We aimed to develop a decision aid that estimates whether treatment of latent tuberculosis infection (LTBI) is likely to have a net gain in quality-adjusted life-years for an individual. A Markov model was developed which incorporated personalised estimates for risk of tuberculosis (TB) reactivation, TB death, quality-of-life impairments and treatment side-effects. The net effect of LTBI treatment was quantified in terms of quality-adjusted life-years gained or lost. Analyses were conducted for a representative set of hypothetical patients. LTBI treatment was estimated to be beneficial when the annual risk of TB reactivation exceeded 13/100 000 to 93/100 000 for females aged 10-75 years and 15/100 000 to 119/100 000 for males aged 10-75 years; the numbers needed to treat to avoid one case of TB were 93, 77, 85 and 72, respectively, at these threshold levels. LTBI treatment was estimated to confer a positive net benefit across a broad range of patients with characteristics typically seen in a low incidence setting for TB. Use of the decision aid has the potential to facilitate and increase confidence with LTBI treatment decisions by providing clinicians and patients with personalised estimates of likely net benefit.