Organs situated within coelomic cavities, that is, heart, lungs and intestinal organs, are surrounded by mesothelial cells throughout life. We and others have shown previously that mesothelial cells contribute to the formation of the vasculature in these organs during embryonic development. Specifically, embryonic epicardial cells, the mesothelial cells encasing the heart, play an important role during coronary vessel formation. But will adult mesothelial cells retain the potential to give rise to vascular smooth muscle cells? On the one hand we have analysed the potential of adult mesothelial cells to respond during angiogenesis in vitro. We have previously developed a method to culture mesothelial cells derived from adult murine omentum. Here we will reveal how adult mesothelial cells respond to signals released during angiogenesis by aligning with endothelial tubes in vitro. In addition, aligned adult mesothelial cells strongly express α-SMA. On the other hand, we will present evidence that adult mesothelial cells express various progenitor markers. Together with their cellular appearance, this finding suggests that progenitor cells are present within the population of adult mesothelial cells isolated from the omentum. In current ongoing studies we are characterising in detail these potential mesothelial progenitor cells and their differentiation potential.