This paper studied the effect of the hybridization of carbon and Kevlar fibers on mode I interlaminar fracture toughness and crack propagation behaviors with double cantilever beam (DCB) tests. The crack propagation characteristics, crack growth trend and rate, and fracture surfaces were observed using an optical microscope and SEM micrographs for the three different types of materials. Moreover, details of the stress distribution around the crack tip and the crack propagation pattern across the width of the DCB specimen were investigated using the finite element method, including a cohesive element. The mode I interlaminar fracture toughness of carbon-Kevlar hybrid/epoxy was nearly average for carbon/epoxy and Kevlar/epoxy. The maximum load predicted by the numerical method showed good agreement within an error of 5% with the experimental results.