STUDY QUESTION: What are the psychological health, relationship quality and perceived social support outcomes of heterosexual couples who have conceived an infant through identity-release egg donation? SUMMARY ANSWER: Parents' scores on all measures were within the normal range. Egg donation mothers had poorer perceived social support, and egg donation fathers had less optimal psychological health than a comparison group of IVF parents, although these differences were associated with the older age of egg donation parents, rather than being an effect of family type. WHAT IS KNOWN ALREADY: There is limited understanding of the psychological health and couple relationship quality of egg donation parents, and no empirical data on parents' social support, during the first year of parenthood. No studies have included families who have used an identity-release egg donor. The study offers the first examination of the psychological well-being of identity-release egg donation parents. STUDY DESIGN, SIZE, DURATION: This study included 57 families created through identity-release egg donation, and a comparison group of 56 families who had used IVF with their own gametes, recruited through UK fertility clinics. Families were visited at home between October 2013 and June 2015. The sample forms part of a larger study examining family functioning in families created following fertility treatment. PARTICIPANTS/MATERIALS, SETTING, METHOD: All families were heterosexual two-parent families with an infant aged 6-18 months. Mothers and fathers were administered standardised questionnaires assessing psychological health (Edinburgh Postnatal Depression Scale, Trait Anxiety Inventory and Parenting Stress Index-short form), couple relationship quality (Golombok Rust Inventory of Marital State) and perceived social support (Multidimensional Scale of Perceived Social Support). MAIN RESULTS AND THE ROLE OF CHANCE: Scores from the egg donation and IVF parents were within the normal range on all measures. Significant differences were found between the groups indicating less optimal social support in egg donation mothers compared to IVF mothers, and poorer psychological health in egg donation fathers compared to IVF fathers. These differences appeared to be related to the older age of egg donation parents or to twin parenthood, rather than to egg donation per se. No differences were found between the groups in the parents' relationship quality. LIMITATIONS, REASONS FOR CAUTION: It is possible that families who were managing the transition to parenthood less well may have been less likely to participate in research. Fewer IVF than egg donation fathers participated in the study, so the statistical power was lower for comparisons between fathers. WIDER IMPLICATIONS OF THE FINDINGS: The findings are of relevance to UK clinics offering identity-release egg donation. That scores of egg donation parents on measures of psychological well-being were more similar than different to those of IVF parents should prove reassuring to individuals considering this treatment type. As less optimal outcomes were found for egg donation parents on several measures, and these were associated with parental age rather than conception type, it is recommended that clinics discuss with older patients how they may establish a social support network and signpost patients to appropriate post-natal support. STUDY FUNDING, COMPETING INTERESTS: This research was supported by a Wellcome Trust Senior Investigator Award [097857/Z/11/Z] and a CHESS-ESRC studentship. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.