This study evaluated clinical and radiographic twelve-month outcomes of root canal treatments (CT) with smear layer removal, performed in primary teeth, using two different root canal filling materials. Pulpectomy was performed on 27 primary teeth with necrosis or irreversible pulpitis, caused by dental caries or trauma, in 23 children (2-7 years old). A single trained operator performed the CT in a single visit in cases without periapical or interradicular radiolucency (PIR) or in multiple visits in cases with PIR. Participants were selected based on specific inclusion and exclusion criteria, and randomly allocated into two groups: Group 1 (G1) - iodoform paste (iodoform + camphorated parachlorophenol + ointment comprising prednisolone acetate 5.0 mg and rifamycin 1.5 mg); Group 2 (G2) - Calen®/ZO paste. Treated teeth were restored with composite resin immediately after the root canal filling. The outcomes were evaluated clinically and radiographically according to specific criteria. Two blinded and standardized evaluators assessed the radiographic outcomes. We used descriptive analyses due to the small sample size. CTs were performed due to caries lesions in 70.4% of the cases and due to trauma in 29.6%. Only one tooth of G1 was unsuccessful; hence, pulpectomy performance in both groups was not influenced by the filling material, nor by any other analyzed variable. The level of the root canal filling was better in the Calen®/ZO group. The clinical and radiographic twelve-month outcomes indicated successful treatment, independently of the root filling material used.