Background Australia?s Early Parenting Services support families and intervene early in mental health problems in parents. The Victorian Early Parenting Strategy, a platform for government policy recommended a stronger evidence base for early parenting services. Tweddle Child and Family Health Service (TCFHS) is a not-for-profit public sector early parenting centre, which provides residential, day stay, home visiting and outreach programs. This study aimed i) to examine the health, social circumstances and presenting needs of clients attending the Tweddle Day Stay Program (DSP) with infants under 12 months old and ii) to assess the parent mental health and infant behaviour outcomes and the factors associated with program success. Methods A cohort of clients was recruited prior to admission and followed-up 8 weeks after discharge. Data were collected using standardised measures in a study specific questionnaire at baseline, participant?s Tweddle records and a follow-up telephone interview. Health, social circumstances and presenting needs of clients were described. Changes in parents? symptoms of depression and infants? sleep and settling between admission and follow-up were calculated. Multiple regression analyses were conducted to examine factors associated with changes in primary outcomes. Results Of the total 162 clients who were eligible and invited to participate, 115 (72 ) were recruited. Parents admitted to the DSP had worse general self-reported physical and mental health than community samples. Infants of DSP participants were no more likely to be premature or have low birth weight, but significantly more unsettled than other community samples. Participants? mental health and their infants? behaviours were significantly improved after DSP admission. In multivariate analysis, higher depression score at baseline and greater educational attainment were significantly associated with improvements in parents? mental health. Worse unsettled infant behaviours and longer time between discharge and follow up were significantly associated with improvements in infant sleep and settling. Conclusions Tweddle DSPs appear to respond effectively to the needs of families presenting with substantial physical and emotional health morbidity and a range of vulnerabilities by treating parental mental health and infant behaviour problems together. DSPs offer important potential benefits for prevention of more serious family problems and consequent health care cost savings.