Three cases of double primary lung cancer occured synchronously are reported with brief review of literature. The incidence of multiple primary lung cancer relatively rare but may become increasingly prevalent as early detection techinque and cancer therapy has improved. The patients were a 67, 69, and 65-year-old men with doulbe primary lung cancer of different cell type or same cell type with other bronchus origin (squamous cell+small cell, squamous cell+squamous cell, squamous cell+bronchioloaveolar cell) were identified with flexible bronchofiberoscopic biopsies. More careful diagnostic evaluation and management are thought to be necessary.