OBJECTIVES: This study estimated the economic consequences of topical moxifloxacin compared with topical ofloxacin in the treatment of acute infectious conjunctivitis in Scotland (SC), Spain (ES) and the Netherlands(NL). METHODS: The rates of treatment failure, defined as no improvement or worsening symptoms, were estimated by a meta-analysis of randomized controlled trials (RCT) of moxifloxacin. The resources consumed and costs of treatment failure were assessed by a survey of 39 General Practitioners (GP) and 14 Ophthalmologists (OPH). National databases were used to estimate resource costs. The potential economic benefit was estimated, and sensitivity analyses were performed using moxifloxacin’s failure rate advantage from  trials directly comparing the drugs and meta-analysis of patients with confirmed bacterial infection (from 3.3% to 6.5% lower). RESULTS: Treatment failure costs are driven by extra physician consultations,and bacterial cultures.   The average cost of a treatment failure in ES, SC and NL respectively is €38, €72, €53 when managed by a GP compared to OPH estimates of €108, €133, and €215. OPH extremes were €93 to €279€.  Assuming 1.5% of the population experiences acute infectious conjunctivitis and a 10%  failure rate in symptomatic improvement in control group patients, the estimated annual cost of failure ranges from €57,000€ to €322,500 per million inhabitants. Primarily OPH use the studied drugs.  With 4.7% less treatment failure when moxifloxacin instead of ofloxacin is used by OPH, the economic benefit was estimated at €5.1, €6.3, €10.13 per patient in ES, SC and NL respectively. This is a cost saving of approximately 11% on specialist treatment independent of the country.  Sensitivity analysis resulted in an economic benefit from €3.58  to €14.01 as extremes of all countries. CONCLUSIONS: The decrease of treatment failure rate using moxifloxacin instead of ofloxacin in acute infectious conjunctivitis provides an economic benefit in three countries of interest.