We present a case of mixed infection by Trichuris trichiura and Trichuris vulpis in a boy of 8 years old, coming from the state of Oaxaca in M xico. He presented abdominal pain, diarrhea with mucus and blood in addition to straining and tenesmus. We carried out differential identification between the two species of this gender, several treatments were administered and the symptoms disappear. But, the parasitic infection persisted until the last clinical control of the patient. We report the presence of important deformation of Trichuris eggs with the administration of mebendazole and albendazole being more effective the second product. We discuss about the importance of this clinical case and the epidemiological aspects in the transmission of man and dog nematodes.