Aims: The aim of this study was to evaluation the treatment success of the short post technique (mushroom restoration) using a composite resin in severely decayed primary anterior teeth after 6, 12, and 18 months after treatment. Methods: Eighteen children aged 3-5 years with severely decayed primary maxillary anterior teeth (60 anterior maxillary primary teeth in total) were included. Patients were treated under general anesthesia (GA). After pulpectomy, a "mushroom shape" was formed in the root canals for the purpose of retention, and the root canals were filled with zinc oxide-eugenol (ZOE), and the teeth were restored with composite resin. The status of treatment was evaluated clinically and radiographically for periapical radiolucency, pathological root resorption, marginal fracture, and loss of restoration for each treated tooth. All findings were recorded. Results: As a result of the evaluation criteria, the success rates at 6, 12 and 18 months were 86%, 80%, and 71%, respectively. None of the teeth showed apical radiolucency or pathological root resorption at the end of the 18th month period. Conclusion: The short-post (mushroom restorations) technique is a clinically acceptable alternative method for restoration of severely decayed primary teeth. This study supports the feasibility of treatment with this technique for pediatric patients treated under GA.