Development of innovative therapies in intensive care medicine is particularly important since diseases as sepsis, acute respiratory distress syndrome (ARDS) and acute renal injury (AKI) have an elevated morbidity and mortality in spite of current gold-standard approaches. Mesenchymal stem cells (MSC) may have a promising role due to their properties in immunomodulation, tissue reparation and microbial clearance. Preclinical data and results of a systematic review of PubMed, PMC and ClinicalTrials.gov have been included to review the role of MSC therapy in sepsis, ARDS and AKI. A description of MSC biology, sources and benefits in preclinical models was included. A phase I/II clinical trial (RCT) is recruiting neutropenic patients with septic shock. In ARDS, the START trial (Stem cells in ARDS Treatment) is a phase I/II study of bone marrow-derived human MSC (hMSC) that is currently recruiting patients. In AKI, a phase I study has demonstrated the safety of hMSCs infusion in patients undergoing cardiac surgery with high risk to develop AKI. A phase II study is still active. The results of these studies will determine the real feasibility of MSC therapy in critically ill patients.