Direct addition of alkylzirconocenes to activatedalkenes was found, for the first time. Octyl- and decylzirconocene chloride reacted with benzylidenemalononitrile to give the corresponding addition products after hydrolysis in 86% and 79% yield, respectively. Zirconacyclopentanes showed a similar reactivity toward activatedalkenes with a two-electron-withdrawing group. On the other hand, treatment