Background/Purpose Pulpotomy is the amputation of coronally infected pulp tissue to maintain the vitality and function of the radicular pulp. This study was designed to assess the clinical and radiographic success rates of primary molars treated by pulpotomy using diode laser, sodium hypochlorite, or no medication after a follow-up period of 24 months. Methods A retrospective study was conducted by evaluating the success rates of primary molars treated by pulpotomy with diode laser, sodium hypochlorite, or no medication according to the clinical symptoms and signs and radiographic features. Results There were 145 primary molars included in the study. No significant differences in clinical and radiographic success rates were found among primary molars treated by pulpotomy using diode laser, sodium hypochlorite, or no medication, when the teeth were treated by experienced pedodontists and restored with stainless steel crowns. The 2-year clinical success rates for primary molars treated by pulpotomy using diode laser, sodium hypochlorite, or no medication were all 100%. The 2-year radiographic success rates were 90.9%, 100%, and 87.5% for primary molars treated by pulpotomy using diode laser, sodium hypochlorite, or no medication, respectively. However, when the pulpotomy for primary molars was performed by less-experienced residents, a reduced overall success rate from 94% for attending doctors to 58% for residents was found. Conclusion Operators and final restorations are confounding factors for determining the success rate of primary molars treated by pulpotomy. Pulpotomy with diode laser, sodium hypochlorite, or no medication are all acceptable treatments of choice for coronally infected primary molars.