Composite filter media is formed from multiple layers of media material including a nanofiber media layer, where the layers are laminated, bound, or otherwise composited to each other. The composite filter media can comprise at least one nanofiber layer comprising polymeric media material having a geometric mean fiber diameter of about 100 nm to 1 μm, and fibers configured in a gradient such that ratio of the geometric mean diameter of fibers at the upstream face of the nanofiber layer to the geometric mean diameter of fibers at the downstream face of the nanofiber layer is about 1.1 to 2.8, preferably about 1.2 to 2.4.