A hydrocarbon trap is provided for reducing cold-start hydrocarbon emissions. The trap is formed by extruding from about 60 to 80% by weight zeolite and from about 20 to 40% by weight of a binder to form an extruded zeolite monolith. A three-way catalyst and an oxygen storage capacity material may also be included in the trap. The hydrocarbon trap contains from about 5.0 to 8.0 g/in.3 zeolite, which provides increased hydrocarbon retention. The hydrocarbon trap may be positioned in the exhaust gas passage of a vehicle such that hydrocarbons are adsorbed on the trap and stored until the monolith reaches a sufficient temperature for catalyst activation.