To validate the Japanese version of the Patient Health Questionnaire against the Mini-International Neuropsychiatric Interview-Plus in Japan 131 patients in 4 primary care settings and 2 general hospital settings participated. These patients completed the Patient Health Questionnaire and returned it to their physician within 48 hr. Subsequently, the subjects underwent a diagnostic evaluation interview based on the Mini-International Neuropsychiatric Interview-Plus by an interviewer blind to the results of the Patient Health Questionnaire screening. The Patient Health Questionnaire diagnosis was characterized using kappa values between 0.70 and 1.0 for Somatoform Disorder, Major Depressive Disorder, Panic Disorder, Bulimia Nervosa, Alcohol Abuse/Dependence, and Premenstrual Disorder. Sensitivities, specificities, and negative predictive values were very good (between 0.84 and 1.0) for the first 4 diagnoses but not Alcohol Abuse/Dependence or Premenstrual Disorder, as were the Positive predictive values (between 0.78 and 1.0). Findings show very good concordance of the Japanese version of the Patient Health Questionnaire with the Japanese version of the Mini-International Neuropsychiatric Interview-Plus.