20 full-term and 20 preterm infants and their mothers were videotaped in the Strange Situation, and the security of their attachment relationships was later determined. Each episode was subsequently divided into consecutive 15-sec intervals, during each of which ratings of facial expressions were performed. From these ratings several summary dimensions of affect were derived (e.g., affective peak and range during all episodes, latency and rise time for onset of distress during separation episodes, and recovery time during reunions). Term and preterm infants did not differ from one another in either the security of attachment or their affective expression and regulation. When groups were combined, patterns of affective expression were significantly different for infants classified as insecure-avoidant, insecure-ambivalent, and securely attached, as well as for group B1 + B2 infants compared to group B3 + B4 babies. The findings indicated that attachment-related affect may reflect an affect continuum that underlies certain mother- and stranger-directed behaviors in the Strange Situation, but that not all aspects of reunion behavior can be predicted by prior separation reactions.