We report on the design, fabrication, and initial characterization of vertically aligned carbon nanofiber-based microfabricated field emission devices with an integrated out-of-plane electrostatic focusing electrode. The potential placed on this electrode was found to have a profound impact on the diameter of the beam emitted from the device as observed on a phosphor screen. Aspects of the device fabrication process and device operation are discussed. The experimental results obtained are compared to a numerical simulation of device performance and found to be within good agreement. (C) 2004 American Vacuum Society.