A palladium-catalyzed carbonylative Heck-type cyclization of alkyl halides is described. Treatment of a range of primary and secondary alkyl iodides with catalytic palladium(0) under CO pressure forms a variety of synthetically versatile enone products. The reactivity described represents a rare example of a palladium-catalyzed Heck-type cyclization involving unactivated alkyl halides with beta-hydrogens. Alkene substitution is well tolerated, and mono- and bicyclic carbocycles may be easily accessed.