Two child and three elderly patients underwent craniotomy for organized and/or partially calcified chronic subdural hematomas (CSHs). The characteristic feature of magnetic resonance imaging was a heterogeneous web-like structure in the hematoma cavity. Both children had undergone one side subduroperitoneal shunt for bilateral CSHs when infants. As a result, the opposite hematoma cavities persisted and developed into calcified CSHs after a couple of years. All three elderly patients with senile brain atrophy showed various systemic complications such as cerebral infarction, diabetes mellitus, leg ulceration, cirrhosis, and bleeding tendency. Craniotomy for removal of the hematoma and calcification achieved good results in all patients. Subdural space created by shunt, craniotomy, or brain atrophy and persisting for a certain period, and additional various brain damage such as microcirculatory disorder, meningitis, encephalitis, or premature delivery may be important in generating calcified or organized CSH.