Objective: The objective of this study was conducted to evaluate clinically and radiographically the effectiveness of acemannan as direct pulp capping material in young permanent teeth. Subjects and Methods: The present study was performed on thirty six mandibular first young permanent molars with deep carious lesion indicated for direct pulp capping. The children aged from six to nine years old. After completely removing the infected dentine, teeth with a pinpoint pulpal exposure were randomly divided into two treatment groups: (group A) Acemannan or (group B) calcium hydroxide paste. In both groups, the remaining part of the cavity was filled with resin-modified glass ionomer filling. The teeth were assessed clinically and radiographically at different intervals (48 hours, 1.5 month and 3 months post-operative). Results: The present study revealed that, the clinical and radiographic success rate of acemannan was (77.8%), while Calcium hydroxide group showed a higher success rate (83.3%). Conclusion: Although the acemannan is a promising material but calcium hydroxide offers good clinical and radiographic results and success than acemannan but with no statistically significant differences.