Abstract. Lactobacillus rhamnosus is usually regarded as a nonpathogenic, commensal organism. We report a case of L. rhamnosus sepsis in a preterm, extremely low birth weight infant not associated with probiotic administration. Our case and literature review indicate that L. rhamnosus should be considered a potentially pathogenic organism. Microbiologic identification is important for optimal treatment as many are resistant to commonly used antibiotic regimens.