Background: The department of pharmacy at the National Cancer Center Hospital East is the first hospital which has performed outpatient pharmacy service which pharmacists work with oncologists at outpatient clinic booth in Japan since 2007 in Japan. The pharmacists shared oncologist outpatient, and explained and instruct medicines for patients in beside oncologists. Objective: To evaluate the outpatient pharmacy service, we conducted a questionnaire survey. Methods: We conducted questionnaire survey for 24 oncologists from six medical division and 13 nurses, who have worked with the outpatient pharmacists and 192 patients who received the outpatient pharmacy service. Results: The response rate was 83% (n=20) from oncologists. The usefulness of the pharmacy service was “very useful” (n=16, 80%) and “useful” (n=4, 20%). Average estimated percentage of reduction in medical examination due to the pharmacy service was 24 ± 14 (S.D.) and estimated health reimbursement fee by oncologists was JPY 1560 ± 740. The response rate was 85% (n=11) from nurses. The usefulness of the pharmacy service was “very useful” (n=9, 82%) and “useful” (n=2, 18%). Estimated health reimbursement fee by nurses was JPY 1310 ± 550. The response rate was 92% (n=177) from patients who had received the outpatient pharmacy service at least two times. The usefulness of the pharmacy service was “very useful” (n=101, 57%) and “useful” (n=73, 41%). Conclusions: The study clarified that the outpatient collaborating pharmacy service with oncologists at an outpatient booth was beneficial.