Although some lymphatic plexuses exist in lower quadrants of the breast, there have been no investigations of whether or not carcinoma located in this region is a prognostic factor for breast cancer. Of 914 patients with carcinoma of the breast who underwent curative resection following chemo-endocrine therapy between 1982 and 1985, 149 patients had disease of the lower quadrants. The recurrence-free survival rate was lower in patients with the lower quadrants carcinoma than in those with carcinoma of other breast regions. Multivariate analysis showed that a lower quadrant tumor location was a significant prognostic factor for recurrence, especially soft tissue and visceral recurrence. The worse prognosis of patients with lower quadrant carcinoma of the breast suggests the possible existence of residual or occult tumor cells after surgical resection.