Disclosed is a composition for the prophylaxis or therapy of intraventricular hemorrhage in preterm infants comprising mensenchymal stem cells. Functioning to prevent ventricular dilatation and reduce the level of inflammatory cytokines in cerebrospinal fluid, the composition comprising mesenchymal stem cells is advantageously useful for the prophylaxis or therapy of intraventricular hemorrhage in preterm infants. Accordingly, the composition is effectively preventive of hydrocephalus which occurs subsequent to intraventricular hemorrhage. In addition, the composition makes not only a histological and biochemical recuperation in the intraventricular hemorrhage-injured brain, but also significantly improves sensory motor functions. Mesenchymal stem cells can be used as an effective therapeutic agent because they are less prone to induce immune rejection responses and are highly likely to secrete proliferative, differentiative, and regulatory factors. Hence, mesenchymal stem cells are expected to play a critical role in the therapy of intraventricular hemorrhage in preterm infants.