The effect of sampling site and closeness of malignant tumor on the retinoid, carotenoid, tocopherol, and tocotrienol concentration of adipose tissue of human breast was studied in 10 cases of breast cancer. The four anatomic quadrants of breast did not differ from each other statistically significantly in relation to adipose tissue concentrations of the vitamins studied. Proximity of malignant tumor did not affect the vitamin concentrations when compared to the more distant sampling sites. Representative sample of breast adipose tissue for vitamin concentration analysis can be obtained from tissue adjacent to the tumor.