This investigation is an attempt to test the common supposition that postpartum emotional disturbance is related to hormone changes. A group of 27 normal pregnant women were assessed three times before delivery and sixteen times in the six weeks following delivery. During the first two interviews baseline data on personality and other personal variables were obtained. On each occasion blood was taken and three measures of clinical status and mood were completed. Plasma LH, FSH, total oestrogen and progesterone results are presented in detail and the results of prolactin assays mentioned more briefly. An attempt to correlate hormone findings and clinical findings is described. This failed to produce any strong evidence that hormones are related to mood at this time, although hormone changes were correlated weakly with a few specific symptoms. Some of the unexpected clinical findings and technical difficulties of the study are discussed, with special reference to possible further research in this area.