The mother-infant relationship has an important influence on maternal mental health and infant development. Evidence suggests that this relationship is enhanced by a mother's sensitive response towards her infant's distress. We proposed that attentional processing of infant distress may indicate individual differences in this response. Research also suggests that maternal responses develop during pregnancy. We therefore hypothesised that more sensitive attentional processing of distressed infant stimuli during late pregnancy will be associated with more successful mother-infant relationships. Healthy pregnant women were recruited through community midwives. An established computerised paradigm measured women's ability to disengage attention from distressed or non-distressed infant faces. From this paradigm, we derived an index of women's attentional bias towards infant distress. Mother-infant relationships were measured using the postpartum bonding questionnaire (PBQ). A complete case sample of 49 women completed the attentional paradigm during late pregnancy and the PBQ 3-6 months after birth. We found that women who showed greater attentional bias towards infant distress during late pregnancy reported more successful mother-infant relationships. For every 50-ms increase on our measure of attentional bias towards infant distress during late pregnancy, the odds ratio for reporting a higher PBQ score, indicative of a weaker relationship, was 0.43 (95% confidence intervals 0.23-0.81, p = 0.01). The results suggest that women's basic attentional processing of infant emotion during pregnancy influences their relationships with their infant. In the future, women's attentional processing of infant emotion could inform early strategies to promote successful mother-infant relationships in vulnerable mothers to be.