The present study was conducted to clarify the time course of anxiety and illness management behavior in mothers of infants with congenital cyanotic heart disease during the first month following hospital discharge. The study population comprised 11 mothers of infants with congenital cyanotic heart disease. Four surveys were conducted using questionnaires and interviews: before discharge and at 1, 2 and 4 weeks after discharge. Anxiety scores obtained from the subject mothers using the state-trait anxiety inventory (STAI) were analyzed statistically by t-test, and interview findings were analyzed qualitatively. The mean anxiety score was at maximum before discharge and had decreased at 1 week after discharge, at which time the mothers exhibited a significant improvement in behavior regarding the medication for their children's disease and their action and attitude toward the crying of their children as a result of trial-and-error efforts in child care and disease management. Also the mean anxiety score of mothers not experienced in patient care at home was higher than that of mothers experienced in patient care at home and the anxiety score at 1 week after discharge was higher significantly. At 2 weeks after discharge, two thirds of the mothers came to understand more fully their children's life patterns and felt that the children had become accustomed to live at home.