Data regarding the efficacy and safety of methotrexate (MTX) in adults with localized scleroderma (LoS) is scarce. This study gathered data from a retrospective cohort of adult patients with LoS (n?=?107), treated with MTX (1993-2015). MTX drug survival and predictors thereof were analysed. After 1 and 2 years, 26% and 63% of patients stopped MTX due to disease remission, respectively. Patients with younger age at MTX initiation (hazard ratio (HR) 1.159 (95% confidence interval (CI) 1.052-1.277)) and those with no other autoimmune diseases (HR 3.268 (95% CI 1.334-8.009)) more often stopped MTX due to disease remission. In addition, 24% of patients stopped MTX due to treatment failure within one year. Patients with circumscribed superficial LoS (HR 0.221 (95% CI 0.081-0.601)) experienced treatment failure less often than those with other LoS subtypes. Finally, adding folic acid (HR 0.184 (95% CI 0.079-0.425)) and reducing treatment delay (HR 1.056 (95% CI 1.004-1.112)) could be the most important factors in minimizing MTX treatment failure in LoS in clinical practice.