The echographic and histological data on regional lymph nodes in 56 cases of stomach cancer were evaluated. Microwave examinations offer a sensitivity of 91.1% and a specificity of 30.4% for this localization. Although a focus of hyperplasia cannot be differentiated from a metastatic lesion on the basis of echographic evidence, enlargements of microwave examination-established patterns might suggest a more thorough revision of areas of regional metastases, intrasurgical biopsy, in situ cytologic examination and possibly an extended lymphadenectomy during surgery.