Commercial fermented milks have health benefit potential attributed to pure probiotics used as starter culture. Lactic acid bacteria (LABs) are the probiotics used. LABs promote stabilization of the gastrointestinal microecology of humans by producing secondary metabolites like lactic, acetic and propionic acid, hydrogen peroxide and bacteriocins (bactericidal proteins). These metabolites are health benefiting. Mursik, an indigenous fermented milk product is consumed by many Kenyan communities, specifically the Kalenjin. The fermentation of mursik is not based on pure cultures, instead it is spontaneous. Whether the types and concentrations of the probiotics in this traditionally fermented milk have the same probiotic potential as those of commercial fermented milk is not documented. This study aimed at isolating mursik probiotics and determining their probiotic potential.