ABSTRACT. Almeida V.A., Guedes P.E.B., Muniz-Neta E.S., Magalhães H. & Munhoz A.D. [Influence of gastrointestinal parasitism in the calcium, phosphorus, serics magnesium, and proteinogram in naturally infected dogs.]. Influência do parasitismo gastrointestinal nos níveis de cálcio, fósforo, magnésio séricos e proteinograma de cães naturalmente infectados. Revista Brasileira de Medicina Veterinária, 34(3):198-201, 2012. Laboratório de Análises Clínicas Veterinárias, Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Rodovia Ilhéus-Itabuna, Km 16, Salobrinho, Ilhéus, BA 45662000, Brasil. E-mail: firstname.lastname@example.org The aim of this work was to evaluate serum levels of calcium (Ca), ionized calcium, phosphorus (P), magnesium (Mg) and proteinogram in gastrointestinal parasitism. Were collected samples of blood and feces of 33 dogs, being held the dosage of serum Ca, P, Mg, proteinogram and was done exams by parasitological methods of Hoffman and Faust, in all dogs. Then the animals were treated with anthelmintic Pyrantel pamoate (14.4 mg / kg) and Prazinquantel (5mg/kg), and a second dose was done after 15 days. After ten days, a second collect blood and feces was performed to analyze the same parameters. The study was divided into first phase (before anti-helminthic treated) and second phase (after anti-helminthic treated), and the dogs were divided into two groups, I (positive for gastrointestinal helminthes in the first phase) and II (negative for gastrointestinal helminthes in the first phase). After analyzing the results we could conclude that: hypoalbuminemia with decreased albumin / globulin ratio is the main finding in dogs without clinical signs naturally infected with gastrointestinal helminthes and the time interval of 30 days, after anti-helminthic treated, doesn’t show significant variations in mineralogram and proteinogram of animals.