Frozen shoulder is a common condition resulting in pain, stiffness and functional impairment. Symptoms can persist for months or even years if left untreated. Various treatments are available, but a standard care package does not exist and the most cost-effective treatment has not been established. The objective of this study was to conduct a service evaluation of current practice to establish the effectiveness of corticosteroid injection and physiotherapy intervention and the costs associated. A review of all patients with a diagnosis of frozen shoulder who had received a corticosteroid injection and physiotherapy was undertaken for a 12-month period at a single NHS hospital in the UK. Patient-reported outcome measures were analysed and the costs for treatment calculated. Out of the 55 patients, 43 were happy to be discharged following treatment. Ten were referred for a surgical opinion and two were lost to follow-up. The median pain rating significantly reduced from 8 (interquartile range (IQR) 7, 9) to 2 (IQR 0, 3.75) (p < 0.001). Of the patients, 62 % reported a greater than 60 % improvement. On average, patients attended for an initial consultation and four follow-up sessions at a total cost to the NHS of £135. Based on this small service evaluation study, corticosteroid injection administered by an experienced physiotherapist with follow-up physiotherapy appears to be an effective treatment for frozen shoulder.