Resumen : El objetivo del estudio fue evaluar la capacidad inmunomoduladora de dos cepas de L. paracasei (66 y 71) y una de L. rhamnosus (75) aisladas de leche materna y heces de lactante, en Merida, Venezuela, caracterizadas como potencialmente probioticas en estudios previos. Las bacterias fueron administradas a ratones BALB/c en el agua de bebida durante 7 dias. Con los fluidos intestinales se realizaron pruebas de ELISA para determinar los valores de las citoquinas IFN-γ e IL-10. Se realizo la coloracion de hematoxilina-eosina a cortes histologicos del intestino delgado para observar posibles reacciones inflamatorias. Para el analisis estadistico, se utilizo la prueba de ANOVA de una via, seguido del test post hoc de Tukey, considerando a p<0,05 como significativo. Se observaron incrementos significativos, por encima del grupo control, en las concentraciones de IFN-γ e IL-10 en el fluido intestinal de los ratones alimentados con las cepas 71 y 75. No se observaron reacciones inflamatorias en el intestino delgado. Al inducir un aumento en la produccion de las citoquinas, estas cepas fueron capaces de estimular el sistema inmune manteniendo la homeostasis, por lo que pueden ser utilizadas como adyuvantes del sistema inmune intestinal, sin producir efectos secundarios indeseables. Immunomodulating capacity of potentially probiotic Lactobacillus strains isolated from human breast milk and lactating children feces Abstract : The objective of this study was to evaluate the immunomodulating capacity of two L. paracasei strains (66 and 71), and one L. rhamnosus (75) isolated from breast milk and lactating children feces in Merida, Venezuela, characterized as potentially probiotic in previous studies. The bacteria were administered to BALB/c mice in their drinking water during 7 days. Intestinal fluids were tested by ELISA to determine IFN-γ and IL-10 cytokines values. Histological sections of the small intestine were stained with hematoxilin-eosin to detect possible inflammatory reactions. The statistical analysis was done by a one way ANOVA, followed by the Tukey post hoc test, considering p<0.05 as significant. There were significant increases, as compared with the control group, of INF-γ and IL.10 concentrations in the intestinal fluid of mice fed with strains 71 and 75. There were no inflammatory reactions of the small intestine tissue. By inducing an increase in cytokine production, these strains were capable of stimulating the immune system maintaining homeostasis, due to which they can be used as adjuvant of the immune intestinal system, without producing undesirable side effects.