Background: Improvements in cancer therapies have led to significant increases in survival for many types of cancer, including nasopharyngeal carcinoma (NPC).This in turn has focused attention on the problem of second primary tumors (SPTs) which represent a significant cause of morbidity and mortality for cancer survivors.While numerous studies have examined SPTs in cancer survivors, only a few have looked at SPTs associated with NPC, which is rare in most of the world, but is the most common cancer in young adults in Hong Kong.These studies have produced inconsistent results in regards to whether NPC patients are at increased risk of other malignancies.Methods: Medical records were reviewed for a retrospective cohort of 1462 NPC patients from two Hong Kong oncology centers.Data were collected on incidence of cancers before and after the index NPC case, demographics variables, smoking history, and variables related to disease characteristics and treatment.Results: The mean age of the patients at NPC diagnosis was 49.4 and 74% were males.There were a total of 73 second malignancies recorded (5.0% of the cohort).The most common SPT sites were lung and bronchus (18), colorectum (9), tongue (7), brain (3), HCC (3), female breast (3), nasal cavity (3) and lymphoma (3).Rates in excess of expectations were found for cancers of the lung and bronchus, and especially cancers of the tongue and nasal cavity.While older patients had higher overall SPT rates cancers of the lung and tongue occurred frequently among younger NPC survivors.Discussion: Physicians should be aware of the risk of SPTs for NPC survivors when they plan their patient follow-up.