Apart from experimental and functional investigations, lymphatic scintigraphy has once more become of interest for clinical diagnosis today after replacement of the formerly used 198Au colloid by appropriate 99Tc-labeled microcolloids and after gamma cameras with connected computer are used instead of scanners. In contrast to lymphangiography, lymphatic scintigraphy can be performed after a simple interstitial injection and is also not subject to side effects and possible complications. It also permits examination of body regions which are not accessible to lymphangiography. Largely normal or only slightly damaged lymph nodes are shown scintigraphically. Lymph node size and small lymph node metastases also cannot be detected due to the limited resolution capacity of scintigraphy. Scintigraphic investigation thus provides functional data and in clinical diagnosis mostly only provides indirect pointers to an involvement of lymph nodes in malignancies. The most important clinical indications for lymphatic scintigraphy today are the establishment of: the lymphatic drainage conditions of malignant melanomas of the trunk, the shoulders as well as of the neck and scalp, an involvement of the internal mammary lymphatics in breast cancer, an involvement of the lymph nodes in malignant tumors of the true pelvis (internal iliac lymph nodes), the lymph kinetics in lymph edema (differentiation between primary and secondary lymphedema).