Methane, carbon monoxide, and non-methane hydrocarbons were measured in seven profiles from the boundary layer up to 13 km over the Pacific Ocean off the west coast of the United States and over Alaska in April 1985. Mid-latitude profiles displayed the altitudinal variability of hydrocarbons and CO in the marine troposphere. Mixing ratios, in general, decreased with increasing altitude. Over Alaska, mixing ratios of hydrocarbons and CO were higher than at mid-latitudes, Most profiles showed measureable mixing ratios of many hydrocarbons up to the tropopause and suggested that many non-methane hydrocarbons may be presented through the troposphere in the northern hemisphere. ¿American Geophysical Union 1990