ObjectiveTo investigate the direct economic loss caused by oral infection in patients with acute leukemia. MethodsAcute leukemia patients with oral infection in a tertiary firstclass hospital in Shandong Province between January 2011 and December 2013 were investigated, the 1:1 matched case  control method was used for comparing hospitalization expense and length of hospital stay between oral infected (case group) and uninfected patients(control group). ResultsA total of 994 patients with acute leukemia were monitored, 277 had healthcareassociated infection, 17 (5.56%）of whom were with oral infection. The median hospitalization expense of patients in case group and control group was￥37 327 and￥13 176 respectively, the total hospitalization expense of patients in case group was 2.83 times more than control group, difference was statistically significant （Z=-3.621，P＜0.001). Each hospitalization expense of case group was higher than control group,  especially expense for medicine, blood transfusion, laboratory examination, and therapy. The median length of hospital stay in case group and control group were 17 days and 11 days respectively, rank sum test showed that difference in median length of hospital stay between two groups was statistically significant (Z=-3.627, P< 0.001).  ConclusionAcute leukemia patients with oral infection have increased hospitalization expense, prolonged length of hospital stay, and increased the financial burden.