Twenty-one patients with bipolar affective disorder (20 manic episodes, one depressive episode) during the postpartum period were evaluated. They were compared to an unselected group of women with bipolar histories, as well as to a matched control group. The postpartum group had significantly more Schneiderian symptoms and fewer recurrences of illness within the three-year period after the index admission. There was a notable trend toward postpartum patients having fewer affectively ill relatives than the controls. The practical significance of these findings with regards to lithium therapy is discussed, as is the theoretical significance in terms of heterogeneity of the bipolar syndrome.