To increase our understanding of developmental aspects of the Five Factor Model (FFM) of personality, prospective relations from infant temperament and attachment security to the 'Big Five' dimensions of personality in middle childhood were studied in a sample of 85 Swedish middle class children. Combined maternal and paternal temperament ratings at infant age 20 months and Strange Situation attachment to mother at 15 months were used as predictors of mother and teacher ratings of personality at child age 8 - 9 years. Also the A1 - B2 versus B3 - C2 classification grouping was used as a measure of infant negative emotionality. The results showed extraversion/surgency to be the dimension most clearly related to infancy data; it was predicted by both temperament and attachment security. Attachment security also predicted neuroticism and openness. The emotionality shown in the Strange Situation was not related to the 'Big Five'. The results were discussed in terms of approach and anxiety systems and internal working models as foundations for the FFM personality traits.