Lymphedema most frequently occurs in females aged over 40 years old and is difficult to effectively cure. There are two types of lympfedema: primary and secondary. The etiology of the former is not clearly understood, whereas that of the latter is able to be defined. In this paper, we discuss the incidence of lymphedema in Japan, as well as its etiology, and the current diagnostic manuevers and treatments. We also present a characteristic lymphedema case in our clinic. The main treatment is physical, while adjunctive therapies such as pharmaceutical or intraarterial lymphocyte injection treatments have been performed in some cases. Surgical therapy has not proven to be particularly effective in the treatment of this disease.