The high overall prevalence of giardiasis (45.0%) observed in the present study confirms the important role of pet rodents as reservoirs of Giardia infection. Given that pet rodents are frequently purchased for and kept in close contact with young children, sensitive and regular screening for giardiasis is essential for limiting potential rodent-to-human transmission, particularly as infections in small mammals are often asymptomatic. The aim of this study was to evaluate whether commercially available immunochromatographic tests detecting Giardia antigen registered for dogs and cats can be successfully applied for the examination of rodent faecal samples. Immunochromatographic (IC) antigen assays based on the detection of the Giardia-specific antigen GSA-65 demonstrated high diagnostic utility. In comparison with conventional microscopic methods, IC testing showed an approximately 27% higher diagnostic sensitivity, substantially increasing the detectability of Giardia infection in faecal samples. Owing to the presence of GSA-65 across different species and assemblages of the genus Giardia, commercially available IC tests registered for dogs and cats can be effectively applied off-label in the diagnosis of giardiasis in rodents. Molecular analysis performed on samples positive by microscopy and/or IC testing confirmed the presence of parasites belonging to the Giardia intestinalis species complex, with predominance of the rodent-adapted assemblage G and sporadic detection of zoonotic assemblages A and B. These findings emphasize the added value of combining immunological, parasitological and molecular methods for accurate diagnosis and epidemiological assessment. Overall, the results of this study highlight the relevance of giardiasis in pet rodents and stress the importance of sensitive diagnostic approaches in veterinary practice, with clear implications for public health and the prevention of giardiasis.