Contribution to the establishment and /or improvement of study on some criteria of cytologic diagnosis 5 major lung carcinomas. 50 cases of lung cancer including 14 squamous carcinomas, 18 adenocarcinomas, 8 large cell carcinomas, 8 small cell carcinomas and 2 adeno-squamous carcinomas were diagnosed cytologically and confirmed by histological confrontation. Criteria of cytologic diagnosis were presented and discussed.