The studies reported had two purposes: (a) to identify psychological symptoms commonly experienced by mothers in the first few days after childbirth; (b) to use psychometric methods to develop a questionnaire for detecting and measuring these symptoms. A draft 49-item questionnaire was derived by asking 100 newly delivered mothers to volunteer suitable items. The number of items was systematically reduced to 28 while testing the questionnaire on two further samples of newly delivered mothers (n = 100 and n = 50). Cluster analysis of the 28 items yielded seven clusters, the robustness of which was established in a further sample of 87 newly delivered mothers. The validity of the 28-item questionnaire was established. The questionnaire was quick and easy to administer, suitable for repeated administration on consecutive days, and well accepted by mothers.