Se procesó un total de 290 muestras fecales en el Laboratorio de Protozoologia del College of Medicine Veterinary en Mississippi State University, EUA. Las muestras fueron seleccionadas aleatoriamente en 19 fincas lecheras de 10 condados del estado de Mississippi. Dichas muestras se analizaron con la finalidad de conocer la prevalencia y correlación existente entre los parásitos Cryptosporidium, Giardia y Eimeria. Se utilizaron las técnicas siguientes: concentración por flotación con azúcar (Sheater's), coloración Kinyoun (especifica para Cryptosporidium) e Inmunofiurorescencia. La edad de los animales osciló entre 4 días y 8 meses. Resultaron positivas a la presencia de parásitos Cryptosporidium spp., Giardia spp., Eimeria spp. 18 fincas (94,7%) con 120 muestras (41,3%) del total de muestras analizadas. Para Cryptosporidium spp. 69 (57,5%) muestras resultaron positivas, Giardia spp. 54 (45%) y para Eimeria spp. 30 (25%). Se encontró una correlación entre infestaciones de Cryptosporidium y Giardia en 06 animales, entre Cryptosporidium y Eimeria en 04 animales, y solo siete animales positivos a los tres tipos de parásitos (Cryptosporidium spp, Giardia spp., Eimeria spp.).Fecal samples from 290 bovines randomly selected at 19 dairy farms in ten counties of Mississippi state, USA, were examined during May to August 1995 to investigate the prevalence and association of Cryptosporidium and Giardia infections. Oocysts of Cryptosporidium were identified through the technique of Sheater's sugar flotation, the acid-fast Kinyoun coloration, and Immunofluorescence assay. Age of animals ranged from 4 days to 8 months. Positives animals were found in 18 (94.7%) farms. From total of 290 analyzed samples, 124 (41.3%) were infected: 69 (57.5%) were positive to Cryptosporidium spp., 54 (45%) were positive to Giardia spp., and 30 (25%) were positive to Eimeria spp. Six calves out 120 were positive to both Cryptosporidium and Giardia infection, four were positive to Cryptosporidium and Eimeria infection, and seven animals just had all of three types of parasites.519 -523Bimestral