This chapter provides a reliable and quick method for detection of Giardia duodenalis (which causes a dangerous diarrheal disease), prevention of further spreading, identiication of the source of contamination, and eventually minimize health risk and economic damage normally caused by an outbreak. The loop-mediated isothermal ampliication (LAMP) method is based on the enrichment of parasite-speciic nucleotide sequences, similar to PCR, but it is signiicantly faster and less susceptible to interference. Here, wegive an overview of how we developed this method, and using the example of G. duodenalis as a water-associated pathogen, we present an optimized examination scheme for its detection in water. For this purpose, we have analyzed data from extensive electronic libraries PubMed®/MEDLINE®, iltered out relevant articles with a keyword search, and summarized them. The number of publications on LAMP method has generally increased steadily since its irst report in 2000. LAMP, used for detection of Giardia, especially surpasses all other methods due to the high speciicity, sensitivity, robustness, and cost efectiveness. The ever-increasing number of publications on application of LAMP is similar to the development of PCR in the 1990s of the last century. Certainly, the method will be further developed in future, but it already ofers many advantages over other methods for efective detection of G. duodenalis infections and will therefore certainly gain in popularity.