The relationship between labor pain and concomitant psychological state, in terms of prenatal anxiety levels and post-partum mood, has been studied. A consecutive series of primiparae (n = 129) was assessed at intervals over the course of their pregnancy and after delivery. State anxiety was measured at recruitment (10-14 weeks of pregnancy), 10 weeks, 32 weeks and at labor. Labor pain was assessed on the McGill Pain Questionnaire (MPQ) and visual analog rating scales. Pain ratings on the MPQ were found to be high when compared to other clinical pain groups. Drug use in labor emerged as the strongest predictor of pain ratings on the MPQ total, sensory and affective scales, accounting for 11, 9 and 7% of the variance respectively. Anxiety scores at 32 weeks accounted for a further 5% of the variance and emerged as the best predictor of MPQ evaluative scores and visual analog ratings. A significant association was found between pain ratings and ratings of post-partum mood. Neither attendance at preparatory classes nor initial attitudes towards the neonate were related to pain scores.