BackgroundThe present study evaluates personality traits in adult patients with cystic fibrosis (CF) and correlates these results with health-related quality of life (HRQoL) and other clinical parameters indicative of disease severity.MethodsSeventy adults completed the Cystic Fibrosis Questionnaire-Revised (CFQ-R 14+), a CF-specific measure of HRQoL, and a self-administered questionnaire about personality traits and disorders. Mean subscale scores and the prevalence of extreme personality traits on the `Persönlichkeits-Stil- und Störungs-Inventar (PSSI)´ were compared to the norming sample. Moreover, a cluster analysis was conducted to identify personality styles among people with cystic fibrosis (pwCF). The relationship between mean PSSI subscale scores and personality clusters with HRQoL and clinical outcomes, e.g., percent predicted forced expiratory volume in one second (ppFEV1), and body mass index (BMI), was studied by regression analysis considering important confounders.ResultsOn several of the subscales of the personality questionnaire, people with cystic fibrosis (pwCF) showed either significantly higher or lower scores than the norm sample. In further analyses, two personality clusters could be identified. PwCF from the cluster with predominantly low scores on the subscales ‘negativistic’, ‘schizoid’, ‘borderline’, ‘depressed’, and ‘paranoid’ showed better HRQoL than pwCF from the other cluster with mainly high normal or elevated scores. The studied health outcomes proved to be independent of the respective personality clusters.ConclusionsIn pwCF, HRQoL is mainly determined by psychological factors, including personality. Since more recent personality theories assume that personality is modifiable, our findings imply that patients with accentuated personality traits may benefit from psychosocial support.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12890-023-02463-y.