Rodent maternal separation (MS) is a reliable model of early life stressed-induced alterations in behavior. The gut microbiota of MS rat pups differs from non-separated (NS) controls, suggesting gut-brain axis signaling to be an important mechanism of action. Since dietary factors are known to impact the gut microbiota, this study assessed the impact of consuming prebiotics polydextrose (PDX) and galactooligosaccharide (GOS) with or without the probiotic Lactobacillus rhamnosus GG (LGG) on cognition, social- and anxiety-related behaviors in rodents. Rats were separated from their mothers between postnatal days (pd) 2 to 12. Both MS and NS rats (N=5-9 each) were fed control or prebiotic diet (7 g/kg PDX-GOS) with or without LGG (108 cfu/ml) in drinking water from pd21 throughout behavioral testing to pd100. Overall there were no differences in body weight or food intake across diets. However, the open field test revealed that MS rats traveled a shorter distance with reduced velocity than NS rats (p 0.05). These MS effects were ameliorated by prebiotic feeding (p 0.01) and LGG (p 0.01), but interestingly not when combined. MS rats displayed deficits in spatial memory in the Morris water maze (p 0.05) while rats fed prebiotic plus LGG showed a reversal of this impairment (p=0.05). In conclusion, these results demonstrate that both prebiotics and LGG ameliorate early life stress-induced changes in adult behavior and when combined can improve memory performance.