
An ectopically erupted tooth with infected denigerous cyst within the maxillary sinus is a rare occurrence. A 20 yr old female patient presented with pus discharge, rhinorrhea, halitosis and swelling over the left cheek. It was diagnosed to be a large dentigerous cyst with ectopic tooth in left maxillary sinus. Early diagnosis and treatment is essential as it has greater tenden to produce some resorption of other teeth as compare to other jaw cyst. In this case ths cyst had lined the antral cavity hence enucleation had to be done through Caldwell-Luc approach.