Objective To assess the cost effectiveness of a reduced imaging follow-up protocol of distal radius fractures compared with usual care. Design An economical evaluation conducted alongside a multicentre randomised controlled trial (RCT). Setting Four level-one trauma centres in the Netherlands. Participants 341 patients participated (usual care (n=172), reduced imaging (n=169)). Interventions Patients were randomised to usual care (routine radiography at 1, 2, 6 and 12 weeks) or a reduced imaging strategy (radiographs at 6 and 12 weeks only for a clinical indication). Outcome measures Functional outcome was assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and quality-adjusted life years (QALYs) using the EuroQol-5Dimensions-3 Levels (EQ-5D-3L). Costs were measured using self-reported questionnaires and medical records, and analysed from a societal perspective. Multiple imputation, seemingly unrelated regression analysis and bootstrapping were used to analyse the data. Results Clinical overall outcomes of both groups were comparable. The difference in DASH was -2.03 (95% CI -4.83 to 0.77) and the difference in QALYs was 0.025 (95% CI -0.01 to 0.06). Patients in the reduced imaging group received on average 3.3 radiographs (SD: 1.9) compared with 4.2 (SD: 1.9) in the usual care group. Costs for radiographic imaging were significantly lower in the reduced imaging group than in the usual care group (€-48 per patient, 95% CI -68 to -27). There was no difference in total costs between groups (€-401 per patient, 95% CI -2453 to 1251). The incremental cost-effectiveness ratio (ICER) for QALYs was -15 872; the ICER for the DASH was 198. The probability of reduced imaging being cost effective compared with usual care ranged from 0.8 to 0.9 at a willingness to pay of €20 000/QALY to €80 000/QALY. Conclusions Implementing a reduced imaging strategy in the follow-up of distal radius fractures has a high probability of being cost effective for QALYs, without decreasing functional outcome. We, therefore, recommend imaging only when clinically indicated. Trial registration number The Netherlands trial register (NL4477).