South American ecosystems harbour diverse cricetid rodents and their associated nematode parasites, with implications for ecology and zoonotic risk. We conducted a systematic review following the PRISMA guidelines to catalogue nematode taxa reported from the digestive tract and accessory organs of cricetid rodents in Argentina and Chile. Searches were carried out in five databases (PubMed, WoS, Scopus, SciELO, and Google Scholar) up to 10 January 2026. Parasitological descriptors, such as prevalence (P), mean abundance (MA), and mean intensity (MI) were estimated. We analysed 53 studies examining 4400 rodents (33 species), with Abrothrix olivacea (n = 1000 specimens) and Akodon azarae (n = 775 specimens) most frequently sampled. Ninety-two nematode taxa were reported, with A. olivacea exhibiting the highest richness (17 taxa). Guerrerostrongylus zeta showed the highest P (97.56% in Oligoryzomys nigripes), followed by Stilestrongylus stilesi (92.5% in Necromys lasiurus) Peak infection intensities occurred with Stilestrongylus flavescens in O. flavescens (MA = 72.79/MI = 126.7) and St. stilesi in N. lasiurus (MA = 120/MI = 129.73). This review provides the first comprehensive synthesis of gastrointestinal and hepatopancreatic nematodes in cricetid rodents from Argentina and Chile, highlighting research biases and priorities for advancing our understanding of nematode–cricetid rodent dynamics in the region. The overrepresentation of A. olivacea underscores the need to expand the range of cricetid rodent sampled and to increase the use of non-invasive and molecular diagnostic tools. Addressing these gaps will improve our understanding of nematode diversity and associated zoonotic risks in cricetid rodents in these countries.