This study investigated the diurnal output of saliva cortisol in women with symptoms of depression postnatally. Twenty-one depressed and 30 non-depressed women at 7.5 weeks postpartum, and 21 non-perinatal controls, collected saliva at waking, 30 min, and 3 and 12h postwaking. Women who were not depressed postnatally showed a pattern of cortisol secretion over the day similar to non-perinatal controls. There was a significant difference in diurnal pattern between postnatally depressed and postnatally non-depressed women, due to a difference in the first two time points (waking and +30 min): compared to the other two groups who each had a significant increase in cortisol levels from waking to +30 min, the depressed women had significantly higher cortisol levels at waking and no increase at +30 min. The lack of a morning rise in the depressed women is similar to that reported for posttraumatic stress disorder and chronic fatigue syndrome and may reflect a response, in vulnerable women, to the marked cortisol withdrawal that occurs after delivery.