Caused by the protozoan Giardia lamblia, giardiasis is one of the most common parasitic diarrheal infections affecting humans. Although a variety of antigiardial drugs are available to treat infections in humans, failure of conventional treatment with nitroimidazoles for giardiasis has been increasingly reported. We describe the follow-up of a patient with recurrent giardiasis refractory to nitroimidazoles. Despite the different therapies received, the symptomatology and parasitic forms of G. lamblia persisted in the patient. There is no standard treatment regimen for giardiasis refractory to nitroimidazoles. When treatment failure is confirmed, it is necessary to switch to second-line regimens.