The prognosis after surgical treatment for so-called small sized lung cancer which was less than 2 cm in diameter was mainly evaluated in this study. From the present study, the prognosis after surgery of a small sized lung cancer which less than 1.5 cm diameter of tumor mass could not be necessarily satisfactory because of appearence of recurrence and metastasis after surgical treatment. We concluded that the term of lung cancer in early stage meant permanent curability from prognostic view of long term follow-up. Nevertheless, a small sized lung cancer from 1.0cm to 1.5 cm in diameter of tumor mass did not necessarily result in complete cure rate. Thirteen cases with a small sized carcinoma ranging from 1.0 cm to 2.0 cm in size were subjected to evaluate the prognosis after surgery. The distant metastasis occured in 45.5 % of them except 2 deaths unrelated to car-cinoma. Histological pattern of primary tumor, in which distant metastatic focus was seen in relatively early stage following surgery, showed adenocarcinoma except one of squamous cell carcinoma.