Abstract: A card cage for holding a plurality of printed circuit boards has aerodynamically designed card guides and air deflectors that are configured to direct air flow across components mounted on the printed circuit boards. The card cage has a substantially rectangular frame formed by a pair of side panels, a pair of upper cross members and a pair of lower cross members. A pair of upper card guides are mounted between the upper cross members and a pair of lower card guides are mounted between the lower cross members, the card guides being captively held in parallel relationship to the side panels. The inner facing surface of each card guide is provided with a U-shaped channel that is sized and shaped to slidably receive a printed circuit card. The sidewalls of each card guide taper inwardly from the inner facing surface to the outer facing surface to form a streamlined structure with a narrow head at the outer surface that provides minimum resistance to air flow through the card cage.