This study is a randomised controlled trial comparing outcomes from an 8-week Interpersonal Psychotherapy group (IPT-G) for postnatal depression with 'treatment as usual' (TAU), conducted in a routine community setting in the Australian Capital Territory (ACT). Eligible women were recruited and randomly assigned to either IPT-G or TAU conditions. This study compared outcomes on such variables as depressive symptoms, marital adjustment, social support and mother-infant bond at baseline, mid-treatment, end-of-treatment and 3 months follow-up. Participants were also independently assessed using the Hamilton Depression Rating Scale (HAM-D). 50 women completed baseline assessments and were included in the analysis. Comparisons of treatment conditions showed that by end of treatment both the TAU and IPT-G groups significantly improved in terms of mean depression scores, however, the IPT-G women improved significantly more and had continued improvements at 3 months post therapy. Furthermore, women who received IPT-G displayed significant improvement in terms of marital functioning and perceptions of the mother-infant relationship compared to TAU participants. These findings highlight the potential benefits of an interpersonally based treatment, which not only improves outcomes for the mother but also potentially for the couple and the infant when compared to usual care.