This study explores the significance of Haemonchus contortus as a major parasitic threat to sheep health and productivity. It provides an in-depth review of current knowledge on the parasite’s prevalence, particularly in Hungarian and global contexts. Various diagnostic techniques, including fecal egg counts (FEC), the FAMACHA scoring system, and emerging methods like the peanut agglutinin (PNA) test, are discussed and evaluated. The issue of growing anthelmintic resistance—especially to benzimidazoles—is critically examined, supported by molecular findings from recent studies in Hungary. A case study involving field sampling and analysis adds practical insight to the review. The study concludes with future perspectives on integrated parasite management and the potential use of vaccines like Barbervax in regions where conventional control measures are failing.