Eighty one women were asked to rate their mood on a set of 6 visual analogue scales every day for the first 3 weeks after childbirth. The 6 scales were concerned with happiness, depression, tears, anxiety, irritability and lability. Ratings on the depression, tears and lability scales rose to a sharp peak on the 5th post partum day and declined steadily thereafter. This day 5 peak was the same in primiparae and multiparae, and in breast-and bottle-feeders, and was largely independent of the day of leaving hospital. Women who became clinically depressed later in the puerperium had higher depression and lability ratings, and a more pronounced day 5 peak, than those who did not.