In gastric smears obtained by direct vision fiberoptic brush technique from 78 patients with carcinoma of the stomach, an attempt was made to recognize cytologically the histologic type of the tumor with reference to Lauren's classification. The cytologic diagnosis of intestinal type carcinoma was made in 36/45 positive cases on the basis of an abundant cellularity and the presence of rather large pleomorphic cohesive cells often arranged in sheets with a moderately increased N/C ratio. One case of intramucous and two of "early" invasive carcinoma revealed malignant cells which did not differ from those of the advanced cases. In these cases as well as in some of the advanced ones, atypical epithelial cells were found in addition to the malignant ones; these cells could have derived from the histologic areas of atypical hyperplasia of the gastric mucosa surrounding the carcinoma. 14/15 cases of advanced diffuse carcinoma of the stomach could be cytologically identified on the basis of a scanty cellularity and the presence of rather small, monomorphic poorly differentiated cells with a high N/C ratio. The cytologic diagnosis of the mixed-type carcinoma was made in 2/5 positive cases on the basis of the presence of an admixture of both cell types described above. In two cases of the mixed-type carcinoma, only intestinal type cells were found. In the smears of nine cases of intestinal type carcinoma, one of which was intramucous, and of one case of mixed-type carcinoma, the tumor cells could not be specified. 13/78 cases (16.7%) showed negative cytology. The overall accuracy rate was 83.3 per cent. The statistical analysis of a number of cytologic parameters indicated that morphologic differences between Type I and Type D carcinomas of the stomach do exist and that they can be evaluated for differential diagnostic purposes.