TAFRO (thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and organomegaly) syndrome is an atypical manifestation of Castleman's disease. However, the mechanism underlying this very rare syndrome remains unknown, and there is no established standard treatment. Here we report cases of two young females with TAFRO syndrome who showed similar clinical courses. Both cases showed severe anasarca, ascites, and thrombocytopenia. Although high-dose steroids were ineffective, combination chemotherapy showed remarkable effects. However, both patients developed severe but reversible heart failure after CHOP therapy owing to diffuse cardiomyopathy, which was presumably associated with TAFRO syndrome. Therefore, although combination chemotherapy may be very effective in the treatment of TAFRO syndrome, careful observation for cardiomyopathy development is needed, particularly when using adriamycin-containing regimens.