The clinical and pathologic characteristics of gastric carcinoma in patients younger than 30 are compared with those of patients 30 to 39 years of age. Patients in both age groups had similar symptoms, predominantly undifferentiated neoplasms, and poor prognoses. In both groups, there were significant delays in initiation of definitive treatment because of delays in diagnosis. In 80% of the patients, the malignancy extended beyond the stomach wall at diagnosis, adversely affecting their long-term survival. The 20% five-year survival in both groups indicates the necessity of early diagnosis and aggressive treatment.