OBJECTIVE: To estimate the costs and effects of different treatment strategies with intrapartum antibiotic prophylaxis to prevent early-onset group B streptococcal disease in the Netherlands. The treatment strategies include a risk-based strategy, a screening based strategy, a combined screening/risk based strategy, and the current Dutch guideline. METHODS: A decision analysis model was used to compare the costs and effects of different treatment strategies with no treatment for a hypothetical cohort of 200,000 neonates. Baseline estimates were derived from literature and a survey among parents of GBS children. The analysis was performed from a societal perspective, and costs and effects were discounted at a percentage of 3%. RESULTS: The introduction of a combined screening/risk-based strategy with universal screening in pregnancy providing intrapartum prophylaxis for women with a risk factor or for unscreened women with pre-term labor would prevent 362 of the 600 cases with early-onset GBS for €9200 per QALY gained. The risk-based strategy is also an efficient strategy preventing 379 cases of onset GBS and a cost-effectiveness ratio of €10,200 per QALY gained. The other strategies resulted in lower effects for higher costs. Introducing the PCR test does not lead to more favorable cost-effectiveness ratios. CONCLUSIONS: In the Dutch system the combined screening/risk-based strategy and the risk-based strategy are efficient strategies with reasonable cost-effectiveness.