Physiologically inert perfluorinated gases may be used for lung ventilation imaging by Nuclear Magnetic Resonance (NMR). Because the nuclear concentration in the gas is lower than in tissue, signals from large gas volumes must be integrated to produce an acceptable image quality. After a series of phantom studies, preliminary dog studies have been carried out, using breathable mixtures of CF4 and O2. The resulting images have been compared with Xe ventilation scans. Furthermore, perfluorinated solutions were imaged using phantoms. The results are described and the future potential of the technique discussed.