AbstractIntroduction: There are limited therapeutic options for individuals with fibromyalgia. The aim of this study is to analyze changes in health‐related quality of life and incidence of adverse events of those prescribed cannabis‐based medicinal products (CBMPs) for fibromyalgia.Methods: Patients treated with CBMPs for a minimum of 1 month were identified from the UK Medical Cannabis Registry. Primary outcomes were changes in validated patient‐reported outcome measures (PROMs). Ap‐value of <.050 was deemed statistically significant.Results: In total, 306 patients with fibromyalgia were included for analysis. There were improvements in global health‐related quality of life at 1, 3, 6, and 12 months (p< .0001). The most frequent adverse events were fatigue (n= 75; 24.51%), dry mouth (n= 69; 22.55%), concentration impairment (n= 66; 21.57%), and lethargy (n= 65; 21.24%).Conclusion: CBMP treatment was associated with improvements in fibromyalgia‐specific symptoms, in addition to sleep, anxiety, and health‐related quality of life. Those who reported prior cannabis use appeared to have a greater response. CBMPs were generally well‐tolerated. These results must be interpreted within the limitations of study design.