In 133 patients suspected of hypersensitivity to drugs and 102 control patients without hypersensitivity to drugs, the identification of allergenic drugs was performed by the drug-induced lymphocyte stimulation test (DLST) and the leukocyte migration test (LMT) to compare their usefulness in identifying drug allergies. In the 133 subject patients, the positive rate was 24.8% on the DLST and 60.9% on the LMT (agreement rate; 77.4%); thus, the LMT showed a significantly higher positive rate than the DLST (p<0.000001, χ²-test). In the 102 control patients, the positive rates on the DLST and LMT were 6.9%. In addition, the LMT showed a higher positive rate than the DLST for many hypersensitivity symptoms such as skin eruptions and hepatic injury, and for many drug efficacy categories of the suspected drugs such as antibacterial drugs, etc. Furthermore, the positive rate of the DLST did not change when adjusted for the patients' serum and sex, while that of the LMT increased when adjusted for the patients' serum and was found to be higher in females than in males. Our findings indicate that the LMT may be more useful than the DLST in identifying the causative drug in drug allergies and that its interpretation is influenced by the patient's serum and sex.