Introduction: Curettage is more effective than expectant management in women with suspected incomplete evacuation after misoprostol treatment for first-trimester miscarriage. The cost-effectiveness of curettage vs. expectant management in this group is unknown. Material and methods: From June 2012 until July 2014 we conducted a randomized controlled trial and parallel cohort study in the Netherlands, comparing curettage with expectant management in women with an incomplete evacuation of the uterus after misoprostol treatment for first-trimester miscarriage. Successful treatment was defined as a sonographic finding of an empty uterus 6 weeks after study entry, or an uneventful course. Cost-effectiveness and cost–utility analyses were performed. We included costs of healthcare utilization, informal care and lost productivity. Cost-effectiveness planes and cost-effectiveness acceptability curves were estimated using bootstrapping. Results: We included 256 women from 27 hospitals; 95 curettage and 161 expectant management. Treatment was successful in 96% of the women treated with curettage vs. 83% of the women after expectant management (mean difference 13%, 95% confidence interval 5–20). Mean costs were significantly higher in the curettage group (mean difference €1157; 95% C confidence interval €955–1388). The incremental cost-effectiveness ratio for curettage vs. expectant management was €8586 per successfully treated woman. The cost-effectiveness acceptability curve showed that at a willingness-to-pay of €18 200/extra successfully treated women, the probability that curettage is cost-effective is 95%. Conclusions: Curettage is not cost-effective compared with expectant management in women with an incomplete evacuation of the uterus after misoprostol treatment. This indicates that curettage in this group should be restrained.