99Tcm-dextran was evaluated as a lymphoscintigraphic agent in 10 normal volunteers and 24 patients with breast cancer. 99Tcm-dextran (0.5-1 mCi) in a volume of 0.1-0.2 ml was injected into the posterior rectus sheath in the subcostal site on one side. Scintigrams were obtained at 2-2.5 h after injection and the injection was repeated on the other side. The final image was taken at 4.5-5 h after the first injection. The normal distribution of lymph nodes and anatomical variations in scintigraphic images were first determined in normal subjects. In the patient group, eight scintigrams were evaluated as pathological and the rest as normal. In the 25 women whose lymphoscintigrams were normal the mean number of parasternal nodes visualized was six (range: 3-11). Bilateral symmetrical or asymmetrical chain was observed in 20 subjects (80%) and unilateral chain in five subjects (20%). There was cross-drainage in five subjects (20%). Supraclavicular lymph nodes were visualized in 11 subjects (44%). Varying abnormal images were obtained in eight patients. Our results are in good agreement with those reported in the literature, using radiocolloids. It is concluded that 99Tcm-dextran is a promising agent and may well replace radiocolloids because of the simplicity of the labelling procedure, stability of the label, easy availability and low cost.