Abstract Aim Cannabis‐based medicinal products (CBMPs) are prescribed with increased frequency, despite a paucity of high‐quality randomized controlled trials. The aim of this study is to analyze the early outcomes of the first series of patients prescribed CBMPs in the UK with respect to effects on health‐related quality of life and clinical safety. Methods A prospective case series was performed using the UK Medical Cannabis Registry. Primary outcomes were change in patient‐reported outcomes measures (EQ‐5D‐5L, General Anxiety Disorder‐7 (GAD‐7) and Single‐Item Sleep Quality Scale (SQS)) at 1 and 3 months from baseline. The secondary outcome was the incidence of adverse events. Statistical significance was defined by a P‐value