Abstract : A series of nine saturated and unsaturated hydrocarbons were polymerized by subjecting them to a radio frequency glow discharge at reduced pressures. It was found that acetylene polymerizes most rapidly, followed by ethylene and butadiene, then by propylene, cis-2-butene and isobutylene. The saturated alkanes: methane, ethane, and propane polymerize most slowly. Infrared spectra of the polymers made of ethane ethylene, and acetylene showed that with increasing monomer unsaturation the polymer contained more double bonds, fewer methylene groups, and a greater tendency to be oxidized after preparation. An examination of the mechanism of ethylene polymerization led to the conclusion that a significant amount of oligomerization occurs in the gas phase. In addition it is hypothesized that an important initial step is the partial conversion of ethylene to acetylene.