Resorption is defined as a condition associated with either a physiologic or a pathologic process resulting in a loss of dentin, cementum and sometimes bone. Physiologic resorption is seen in primary teeth that results in their exfoliation. In pathologic resorption early diagnosis and prompt treatment are the key factors to save the tooth. For the best treatment outcome, the clinician should have a very good knowledge of etiopathology of resorptive lesions.