Abstract Objective To describe the prevalence of frailty in a single-centre cohort of patients with PMR and describe its association with health-related quality of life (HRQoL), cognition and sarcopenia. Methods This was a cross-sectional study of patients with PMR, according to 2012 EULAR/ACR Classification Criteria, presenting within 12 months of diagnosis and on treatment with glucocorticoids. Frailty was defined according to the Fried frailty criteria. HRQoL was assessed using Patient-Reported Outcomes Measurement Information System Computerized Adaptive Test (PROMIS-CAT) and cognition was assessed using the Mini-Mental State Examination. Sarcopenia was measured by DXA. Results Forty-one patients were enrolled. Prevalence of frailty and pre-frailty was 17% and 59%, respectively. Frail patients had higher inflammatory markers at diagnosis compared with pre-frail and robust patients. Of 27 patients with DXA results, 26% were sarcopenic. Frail patients had worse physical function, and more pain behaviour and interference compared with pre-frail and robust patients. In univariable analyses, frail patients were more likely to have worse physical function, and more pain behaviour and pain interference, which remained significant after adjusting for age. There were no significant associations between cognition or sarcopenia and frailty. Conclusions In this cohort of PMR patients, there was a higher prevalence of frailty and pre-frailty compared with that reported in community-dwelling elderly. Frailty was associated with worse physical function, and increased pain behaviour and pain interference, differences that were also clinically meaningful. Larger prospective studies are needed to confirm these findings and analyse the association of frailty with other PMR disease outcomes.