An approach was developed to examine the providercost of bone marrow transplantation in hematologicdisorders from the day of admission to the day ofdischarge and follow up for six months. In this study, costing principles have beenreviewed and the retrospective determination of directprovider cost for bone marrow transplantation was usedto the individual medical record. The costs werecalculated per patient related to individual treatmentof each patient with due to volume and unit cost. Thecost data of 56 patients was examined from the relevantdepartments in Chulalongkorn Hospital. The directprovider cost per case treated was averaged to be Bt.645,535, cost per patient with intermediateeffectiveness was Bt.821,590, and cost per patient withfull effectiveness was Bt.1,063,234 ,in 1997's price.The costs were classified by inputs to be capital costand recurrent cost. There were 8.87% of total cost tobe capital costs and the recurrent costs were91.13%,which can be classified into 2 components: thepersonnel cost accounted for 19.16% and the materialcosts were 80.84%. In material costs, the highestcategory was drug cost, 63.27% and the second came theblood cost which was 10.13%. The important implicationof this study was how the hospital would cope with thehigh cost of catastrophic illness among hematologicdisorders. This study provided a basis for SocialSecurity Office to consider the rate appropriate forreimbursement in bone marrow transplantation .