Dynamic contrast enhanced (DCE) MRI is an established technique for measurement of lung perfusion, but requires the administration of contrast agents and a breath hold. Thus, methods for contrast agent free assessment of lung perfusion in free breathing, like phase resolved functional lung (PREFUL) MRI, are desirable. Therefore, in this dual center and dual vendor feasibility study, we validated PREFUL MRI against DCE MRI in patients with CF. Perfusion defect percentage (QDP) maps of both methods were calculated, showing an overlap of 61% for the whole lung. Further, a strong correlation between QDPPREFUL and QDPDCE was found (r=0.70, p=0.005).