  We present a new measurement of the antiproton to proton abundance ratio,
pbar/p, in the cosmic radiation. The HEAT-pbar instrument, a balloon borne
magnet spectrometer with precise rigidity and multiple energy loss measurement
capability, was flown successfully in Spring 2000, at an average atmospheric
depth of 7.2 g/cm^2. A total of 71 antiprotons were identified above the
vertical geomagnetic cut-off rigidity of 4.2 GV. The highest measured proton
energy was 81 GeV. We find that the pbar/p abundance ratio agrees with that
expected from a purely secondary origin of antiprotons produced by primary
protons with a standard soft energy spectrum.
