Meridional profiles of the H2 mixing ratio in surface air were obtained by continuous registrations during a ship cruise from Hamburg, West Germany, to Santo Domingo, Dominican Republic, in 1973. Vertical and meridional profiles in the troposphere were measured during a research flight from Cologne, West Germany, to Punta Arenas, Chile, in 1974. The average H2 mixing ratio of surface air was 0.582¿0.003 ppmv (parts per million by volume) in the northern hemisphere. In the upper troposphere it was found to be 0.561¿0.001 ppmv, 1.3% higher than the average of 0.554¿0.002 ppmv in the upper troposphere of the southern hemisphere. The horizontal distribution appears to be rather uniform. The vertical profiles also exhibited a rather uniform distribution of H2. However, vertical gradients near the ground were occasionally observed. They are ascribed to strong sources and sinks at the surface. The H2 mixing ratio in the lower stratosphere appeared to be slightly higher than that in the troposphere.