We present results of atmospheric gamma ray measurements obtained during two balloon flights from Alice Springs, Australia (&lgr;=-29¿), and Fort Summer, New Mexico, United States of America (&lgr;=43¿) at geomagnetic cutoff rigidities of 8.5 GV and 4.3 GV, respectively. The fluxes, in the energy range of 1--15 MeV, are derived as functions of zenith angle, residual depth, and latitudinal rigidity. We find while the downward moving gamma ray flux at the float level (4.8 g cm-2) is not a strong function of rigidity the upward flux at &lgr;=-29¿ is, on average, by factors of 2 to 4 lower than at &lgr;=43¿. The energy spectra of the downward moving gamma rays at various altitudes are harder than the upward moving gamma rays. The spectral indices for both upward and downward fluxes at &lgr;=-29¿ are lower than at &lgr;=43¿.¿ 1997 American Geophysical Union