The products of the radiolysis of liquid neopentane were examined in detail at several different dose rates and as a function of the concentration of isobutene. The major products from pure neopentane are those expected from reactions of hydrogen atoms and methyl, t-butyl and neopentyl radicals. The major unsaturate formed is isobutene. In addition there are unexpected products in the C 8 and C9 region which result from the reaction of hydrogen atoms with isobutene. When large amounts of isobutene are present, radicals are also scavenged. A dose rate effect is observed in pure neopentane and is attributed mainly to the competition between methyl radicals abstracting hydrogen from neopentane and radical combination reactions, the latter being favored at high dose rates.