Internal parasites impose a huge financial burden for small ruminants across the world with recent estimates in Australia suggesting the cost could be as high as $10AUD per breeding ewe per year. Genetic improvement has to be a key part of any integrated pest management plan for internal parasites. The number of worm eggs per gram of feces (WEC) is known to be a good indicator of internal parasite burden and is moderately heritable in both sheep and goats (h² = 0.2 to 0.3). Breeding for internal parasite resistance is complicated by the fact that several different worm species can be present depending on the location, time of year, management practices and prevailing environmental conditions. In Australia, the national genetic evaluation system (Sheep Genetics) only uses data from Haemonchus contortus and Trichostrongylus spp. to reduce some of the complications caused by these multiple worm species. It is also known that WEC is genetically not the same trait across ages and thus there is benefit in breeders recording multiple assessments throughout the animal’s life. Furthermore, research in Australia suggests that the genetic correlations between different sites across Australia may also be significantly less than one, and thus making it important for breeding animals to be assessed in similar environments to those in which their progeny are expected to exhibit their resistance. These issues make the estimation of breeding values and genetic improvement of this trait more challenging. Despite these challenges ram breeders in Australia have managed to make significant genetic improvements in WEC. Some breeders have reduced WEC by up to 5% per year for the last 15 years, while simultaneously improving other production traits. On-farm, these breeders have reported reduced requirements for drenching, less scouring and greater production. Genomic information has also been incorporated into the routine Sheep Genetics evaluations. Breeders now have the ability to obtain moderately accurate ASBV predictions for WEC (plus a range of other traits) via a simple blood test.