OBJECTIVES: With increasing numbers of termination of pregnancies in Scotland, offering a broader range of contraceptive options can increase the number of women satisfied with their method, leading to reduced discontinuation and the resulting positive consequences. This study aimed at assessing the cost-effectiveness of the etonogestrel (ENG)/ethinyl estradiol (EE) vaginal ring from the Scottish National Health Service (NHS) perspective. METHODS: A decision-analytic model was constructed to estimate the relative cost-effectiveness of the ENG/EE vaginal ring and a weighted, average second-line method (including the transdermal patch, long-acting methods, barrier and natural methods) following the use of oral contraceptives. Effectiveness data were derived from a systematic literature review and clinical trials for the vaginal ring. Costs were based on UK National sources. RESULTS: Versus a weighted, average second-line method, the vaginal ring cost an additional GBP£53 per woman and reduced the rate of unintended pregnancy by 0.0158. The incremental cost-effectiveness ratio (ICER) of the vaginal ring versus a weighted, average second-line method was GBP£3337 per pregnancy averted. This ICER can be viewed as a conservative estimate as this study only assessed the weighted cost per pregnancy and was unable to address the psychological and physical implications which may result from an unintended pregnancy. Discontinuation and failure rates were a key determinant of the cost-effectiveness of the vaginal ring. CONCLUSIONS: Whilst the vaginal ring is more effective and more costly than a weighted, average second-line method from the Scottish NHS perspective, a lack of information surrounding indirect costs, compliance impact and health state utilities warrants further analysis to determine the full cost implications. Collection of quality of life data for unintended pregnancies could assist in deriving an appropriate cost-effectiveness threshold.