The definitive diagnosis of esophageal and gastric carcinoma rests upon histological confirmation of the lesion and it is one of the basis for planning the proper treatment. With the advent of exfoliative citology in 1947 the possibility of studying isolated cells detached from the esophagogastric mucosa became a reality. Later on, the development of the fiberoptic endoscopy permitted the direct observation of the lesion, and histological and citological diagnosis. In this report we publish the results obtained in 270 consecutive cases of esophageal and gastric carcinoma. The biopsies were positive in 86.2% of the cases and the citology was positive in 61.8% of the cases. Both procedures combined yielded 90.3% of positive results. Most false negative studies were related to lesions located in the cervical esophagus, and in the esophago-gastric junction, It is suggested that retrograde esophagoscopy through a gastrostomy could improve the results. The false negative cases of gastric carcinoma are related to inadequate gastric evacuation or to submucosal extension of the tumor. The adequate handling of the specimens is vital if good standards are to be kept.