Renal tissues of 208 autopsied cases were examined. Malignant neoplasm with hematological malignancies often accompanied DIC. Tissue sections were stained with hematoxylin and eosin and Mallory's phosphotungstic acid hematoxylin (PTAH), and were applied for immunoperoxidase method (IP), using antisera against human fibrinogen, FDP-D and FDP-E. Histologically in 80 cases (38%) fibrin or fibrinogen related materials (FRMs) were observed in the glomerular capillary or the intratubular area or in both. FRMs were PTAH or IP positive or both in 23 of the 26 cases (88%) clinically diagnosed as DIC. In the remaining three cases anticoagulants probably interfered with FRMs observation. This study showed the PTAH stain was nonspecific and insensitive to FRMs, and that IP was necessary for a pathological diagnosis of DIC. The presence of FRMs in the renal tubuli is an important finding in confirming DIC. DIC may be present histologically in the absence of clinical DIC symptoms.