Three ethylene-bridged unsymmetric zirconocene dichlorides bearing a cyclopentadienyl unit together with either a tetraphenylcyclopentadienyl- (8), a 7,9-diphenylcyclopent[a]acenaphtha-dienyl- (9) or a fluorenyl group (10) were used for propene polymerization after activation with methylalumoxane (MAO) at 30, 50, 70 and 80 degrees C. Whereas 8 is inactive at all, 9 produces atactic polypropene waxes with high activity. The polypropene products of 10 are syndiotactic with stereoregularities depending on the polymerization temperature as well as on monomer and on MAO concentration.