IntroductionPeople with cystic fibrosis (CF) are living longer and healthier lives with a growing number considering and pursuing parenthood. The decision of whether to become a parent is complex for people with CF, and CF is a major factor in reproductive decision-making. Unfortunately, in people with CF who become parents, there are no prospective studies of disease trajectory, no data on the impact of parenthood on mental health, disease self-management, or quality of life, and no research regarding non-genetic parenthood.Methods and analysisHealth Outcomes of Parents with CF (HOPeCF) is a prospective, multicentre observational cohort study which will enrol 146 new parents with CF of children less than 5 years of age. The primary aim of this 60-month study is to assess the rate of lung function decline as impacted by mental health, parental stress and responsibility, and the use of CF transmembrane conductance regulator modulators. In addition, we will conduct dyadic interviews with a subset of study participants and their key supports (partner/family/friend) to inform future interventions.Ethics and disseminationThis longitudinal, observational multicentre study is a necessary and timely step in understanding parental health outcomes in CF and will provide data essential for care guidance to people with CF, their partners, and healthcare providers. The University of Pittsburgh Institutional Review Board approved this study (STUDY23080161). As people with a variety of paediatric-onset chronic diseases are living longer and considering parenthood, these results may have widespread applicability and will be distributed at international meetings and submitted to peer-reviewed journals.