This paper presents a computational approach for designing, mixed fiber filter media for depth filtration. The goal is to find an optimum solution, given the range, for a set of design parameters: thickness of the media, diameter of microfiber, and diameter of nanotiber, surface area ratio of nanofiber to microfiber and mass of microfiber. The objective of this work is to develop a software program that can be used as an aid to accelerate filter design and reduce the number of laboratory experiments. This program applies a Genetic Algorithm to search for an optimum filter media design based on quality factor which quantifies the filter performance. A user friendly computer program is developed that provides inputs, outputs and controls to design a filter media. The program provides a starting point for constructing filter media for testing and design for particular applications. (c) 2007 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.