The Kyushu Hematology Organization for Treatment Study Group (K-HOT) consisted of 22 institutions specializing in hematology in Kyushu. This study is aimed at reviewing the daily practice of infection control for the treatment of hematological malignancies in our group. Nominal questionnaires were mailed to the hematology department in each institution from November 2001 to April 2002. For the first general surveys, 19 of 22 (86%) institutions responded. The second survey was mailed to the 19 respondents and 17 answered the detailed questionnaires with a response rate of 89%. Prophylactic use of trimethoprim-sulfamethoxazole (ST) against Pneumocystis carinii and anti-mycobacterial drugs in patients who had a history of tuberculosis was routine especially for patients with adult T-cell leukemia/lymphoma (ATL). Furthermore, the neutrophil counts to start a granulocyte-colony stimulating factor appeared to be high in ATL as compared with other hematological malignancies. In the setting of autologous stem cell transplantation (SCT), prophylactic use of acyclovir, immunoglobulin and ST was not routine and was reduced in duration, if used at all, as compared with allogeneic SCT. For allogeneic SCT, the cumulative dose of immunoglobulin significantly varied from institutions to institutions. The benefit of this study is the ability to recognize practical management patterns for infection control.