Aim: This case report aims to describe the importance of early diagnosis, various clinical features, and management of radicular cyst with primary mandibular molar. Background: Radicular cyst is an odontogenic inflammatory cyst in origin seen more frequently in permanent dentition and rarely in the primary dentition. It can develop due to pulp injuries or pulp necrosis caused by deep dental caries or dental trauma. It may adversely affect the normal development and eruption of the permanent succedaneous teeth. Case description: We report a case of radicular cyst in association with the primary mandibular molar and its therapeutic management. Conclusion: The efforts in diagnosing and managing radicular cyst when associated with primary teeth hold a good impact on a child's oral health status. Good amount of bone healing and development of the succedaneous permanent tooth bud in its normal position were observed when managed appropriately. Clinical significance: Early diagnosis, proper treatment planning, appropriate management, and regular follow-ups of radicular cyst in primary dentition hold great importance for pediatric dentists as well as general dentists in routine dental practice.