This clinical report describes the fixed prosthodontic rehabilitation of an infra-occlused deciduous molar. Diagnostic considerations included the patient’s age, occlusal status, condition of the infra-occluded tooth including the degree of infra-occlusion and root resorption, as well as adjacent alveolar bone levels. The procedure involved the design and fabrication of a composite resin onlay, which can be regarded as a rapid and conservative therapeutic choice.