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Cattle, sheep and goats are parasitized by various helminth species, the most important being the gastrointestinal nematodes, lungworms and liver fluke. These pathogens can cause severe disease and affect productivity in all classes of stock and are amongst the most important production-limiting diseases of grazing ruminants in Europe and globally. Essentially, all herds/flocks in a grass-based production system are affected. While in specific cases, mortality can be high, the major economic impact is due to sub-clinical infections causing reduced growth, milk production and fertility. A recent comprehensive study, funded by the EUGLOWORM project, estimated the economic burden in the EU at an annual cost of€ 1 B in dairy cattle and€ 0.3 B in the dairy cattle and meat sheep sector, respectively. A major constraint on the control of helminth infections in livestock is treatment failure due to anthelmintic resistance (AR). Frequent, indiscriminate or inappropriate use of anthelmintic drugs to control these parasites has resulted in selection of drug-resistant helminth populations. AR is now widespread in all the major GIN of sheep and in liver fluke and is an emerging problem in cattle parasites. The economic impact of treatment failures today is unknown, but if no alternatives to current control options become available, pasture-based livestock industries are likely to suffer major economic losses. Here, we review the current knowledge on the development, occurrence, impact and envisaged solutions of AR in ruminant livestock in Europe.