The structure and composition of the Venus upper atmosphere between 130- and 650-km altitude were measured for a solar zenit angle of approximately 60¿ by the neutral gas mass spectrometer on board the Pioneer Venus multiprobe bus. Below 180 km a wavelike structure is quite evident in the CO2 and He number density profiles. For altitudes above 100 km a one-dimensional model of the Venus upper atmosphere during morningside conditions (MS model) is presented. Number densities at 150-km altitude are as follows: CO2 = 4.9¿109, N2 = 1.1¿109, CO = 2.8¿109, and He = 4.8¿106 cm-3. The exospheic temperature is 275 K. The vertical compositional structure is best described by an eddy coefficient K = 1.4¿1013na-1/2 cm2/s, where na is the total number density in units per cubic centimeter. The homopause altitudes for N2 and He are at 136 and 130 km, respectively.