Apparatus (20) for mounting the horizontal compressor (10) of a vapor compression air conditioner to a foundation includes an L-shaped bracket (21) at each compressor end, each bracket having a horizontal leg (21H) adapted for attachment to mounting lugs (11) which extend laterally outwardly from the compressor casing. Each bracket is sized and otherwise configured so that its vertical leg (21V) extends upwardly from the horizontal leg along the outside of an end (102 or 103) of the compressor casing (101) to a point above the drive shaft axis of rotation (A.sub.R) of the compressor motor. A pin (22) is secured to and extends outwardly from the vertical leg of the bracket. The longitudinal axis of each pin is coincident with the driveshaft axis of rotation. Each pin extends into a pin socket (25) in a respective mounting support (24) which is securely fastened to a foundation (30) such as the base pan of an air conditioner. A resilient grommet (23) is disposed between each pin and its respective pin socket and vibrationally isolates the compressor, from the mounting support and the foundation.