The palladium-catalyzed cycloisomerization of acyclic bisdienes to cyclized enedienes defines a novel strategy for the stereoselective cyclization of certain unsymmetric bisdiene substrates to form functionalized five-and six-membered rings. The full details of our investigation into this novel cycloisomerization, including our observations on substrate requirements, stereoselectivity, the influence of the catalyst precursor, and some mechanistic insights drawn from deuterium labeling studies, are discussed.