Measurements on Gametag (Global Atmospheric Measurements Experiment of Tropospheric Aerosols and Gases) in April and May 1978 indicate volume mixing ratios of CH4 of 1.62 ppmv south of the intertropical convergence zone and 1.72 ppmv north of 20¿N. For CO south of 10¿S, the CO volume mixing ratios were rather constant and equal to 57 ppbv. Poleward of 30¿N in the northern hemisphere we measured average mixing ratios of 175 ppbv. Both for CO and for CH4 a gradual transition from lower southern hemispheric to higher northern hemispheric values were observed between 10¿S and 20¿N. The uncertainities in our measurements are 15% for CO and 3% for CH4. By comparing our observations with earlier ones. (Seiler, 1974; Ehhalt, 1978), we can not detect any changes in the atmospheric abundances of CO and CH4 from 1972 to 1978 outside the uncertaintly limits of the measurements.