The present study reports data concerning the discriminant validity of the Carey Infant Temperament Questionnaire. Subjects were 187 primiparous women who completed a battery of psychologic tests prior to the births of their infants. They also filled out the ITQ at three and six months after the baby was born. Nine of the 20 variables derived from the prenatal test battery discriminated mothers whose babies were diagnosed as temperamentally "difficult" from those whose infants were diagnosed as temperamentally "easy" based on three-month ITQ scores. Seven of the prenatal variables similarly discriminated these two groups on the six-month ITQ. The implications of these findings for uses of the ITQ are discussed.