The role of Helicobacter pylori on the development of gastro-duodenal diseases and gastric cancer, demands the availability of reliable tests to diagnose that infectious disease. The rapid urease test, widely used, is a valuable tool for this purpose, but its expense limits the applicability of this test in our country. In this research, the diagnostic validity of a non-commercial inexpensive urease test was evaluated. It was prepared with Christensen’s urea agar, applied to antral gastric biopsies from 75 symptomatic adults who were submitted to digestive endoscopy. The positive result to any of the following methods was used as infection criteria: bacteriologic culture, Giemsa histological stain and polymerase chain reaction 35 out of 37 patients, in whom the infection was detected, were correctly diagnosed by this test (94.6%), and 29 of them (82.8%) were detected after two-hour incubation. The rate of false negatives was significantly reduced, and both sensitivity and diagnostic accuracy were increased in the readings practiced after 24-hour incubation. In conclusion, the performance of the urease test evaluated suggests that this is a highly reliable and low cost tool for the diagnosis of H. pylori infection in individuals submitted to digestive endoscopy.La asociacion entre la infeccion por Helicobacter pylori y el desarrollo de enfermedades gastroduodenales y cancer gastrico, exige disponer de pruebas confiables para diagnosticar esta infeccion. La prueba rapida de ureasa, ampliamente difundida, es una herramienta valiosa para este fin, pero su elevado costo limita su aplicabilidad en nuestro medio. En el presente trabajo se evaluo la validez diagnostica de una prueba de ureasa no comercial y de bajo costo, preparada con agar urea de Christensen, aplicada a biopsias gastricas antrales de 75 adultos sintomaticos, sometidos a endoscopia gastrointestinal. Como criterio de infeccion, se empleo la positividad a cualquiera de las siguientes metodologias: cultivo bacteriologico, coloracion histologica de Giemsa y reaccion en cadena de la polimerasa. De 37 pacientes en quienes se detecto la infeccion, 35 fueron correctamente diagnosticados mediante esta prueba (94.6%). 29 de ellos (82.8%) fueron detectados a las dos horas de incubacion. Al realizar la lectura a las 24 horas de incubacion, se redujo significativamente la tasa de falsos negativos, y se incrementaron la sensibilidad y la exactitud diagnostica. En conclusion, el comportamiento de la prueba de ureasa ensayada sugiere que esta es una herramienta altamente confiable y de bajo costo para el diagnostico de la infeccion por H. pylori en individuos sometidos a endoscopia gastrointestinal.