The aims of this study were to compare 2-year cumulative survival rates of amalgam and atraumatic restorative treatment (ART) restorations in primary molars and to investigate the determinants of the survival rate of restorations. A controlled clinical trial using a parallel group design was carried out on 258 children aged 6-7 years old, allocated to two treatment groups: conventional restorative treatment using amalgam and ART using high-viscosity glass ionomer. A total of 364 amalgam restorations and 386 ART restorations were placed by three pedodontists in 126 and 158 children, respectively, and were evaluated after 0.5, 1, and 2 years. Restorations were placed in vital primary molars with neither pain nor signs of pulp involvement. The survival analysis was conducted using the proportional hazard rate regression model with frailty correction. The 2-year cumulative survival rates for all amalgam (77.3%) and ART (73.5%) restorations were not statistically significantly different, but there was an effect of "type of surface" (single/multiple) and "cavity filling time" on the survival rates. Both amalgam and ART single-surface restorations had higher survival rates than multiple-surface restorations of the same material. Secondary caries was responsible for 36 and 38% of failures in amalgam and ART restorations, respectively. Mean time for restoring all type of cavities with amalgam and ART restorations was 13.6 and 13.7 min, respectively. Amalgam and ART restorations presented similar survival rates over a 2-year period for all, single-surface, and multiple-surface restorations. In the cause of finding alternatives to amalgam, ART restorations using high-viscosity glass ionomer might be a suitable option for managing cavitated dentine carious lesions in vital primary molars.