The microvasculature consists of endothelial cells and their surrounding pericytes. Few studies on the regulatory mechanisms of tumour angiogenesis have focused on pericytes. Here we report the identification of tumour-derived PDGFRβ⁺ (platelet-derived growth factor receptor β) progenitor perivascular cells (PPCs) that have the ability to differentiate into pericytes and regulate vessel stability and vascular survival in tumours. A subset of PDGFRβ⁺ PPCs is recruited from bone marrow to perivascular sites in tumours. Specific inhibition of PDGFRβ signalling eliminates PDGFRβ⁺ PPCs and mature pericytes around tumour vessels, leading to vascular hyperdilation and endothelial cell apoptosis in pancreatic islet tumours of transgenic Rip1Tag2 mice.