The aim of this study was to compare the efficacy of lyophilized freeze dried platelet derived preparation with calcium hydroxide as pulpotomy agents in primary molars. Fifty six primary molars in 28 children were treated by a conventional pulpotomy technique. 28 teeth were treated by lyophilized freeze-dried platelet derived preparation and another 28 by calcium hydroxide. Clinical evaluation was carried out out at 1, 3, and 6-months interval and the radiographic evaluation was carried out at 1 and 6-months. The success rate of lyophilized freeze-dried platelet derived preparation proved better than calcium hydroxide.