The cytology of the stomach aims at detecting the carcinoma. For the obtaining of cell material today mainly endoscopically well-aimed techniques are applied. In other words: The diagnostic results decisively depend on the abilities of the endoscopist who has to discover a suspect region in the stomach and to take off the material in a well-aimed way. Under these aspects and prerequisites, in fact, any type of stomach cancer can be cytologically diagnosed. For the differentiation between tumourous cells and non-tumorous cells the changes of the gastric mucosa with non-malignant diseases are important (chronic gastritis, ulcer, erosion) for the cytologist. Often, with stomach cancer the stomach cell findings resemble those arrived at with non-malignant stomach diseases. Characteristic cytological findings with gastritis, ulcer and erosions are demonstrated. The clinical diagnostics of these diseases is the task of endoscopy and biopsy. The problem of the so-called false positive cell findings is discussed. Ways towards a quantitative diagnostics are being opened by cytophotometric methods. The author states first experience of his own gathered by applying the DNA-determination in individual cells and in the flow-through method.