Polyalkylene glycol (PAG) lubricants have been chosen for use with refrigerant HFC-134a by the mobile air conditioning industry. As this industry gears up to use PAG lubricants, several issues have surfaced regarding the handling of these products. Information will be presented regarding the hygroscopicity and elastomer compatibility of PAG lubricants.Polyalkylene glycols are being evaluated by the automotive industry as retrofit lubricants. PAG lubricants exhibit good stability in the presence of residual CFC-12. Data from retrofit tests performed on compressor test stands will be summarized. This paper will also describe the retrofitting of CFC-12 vehicles to HFC-134a and PAG lubricants.