A great number of studies have been conducted pressure drop for packed bed and curved channel. However, pressure drop in the spiral packed beds has not been investigated. In this study, pressure drop in spiral packed beds which are made of two different channel widths (a = 10 mm and a = 15 mm) and three different ball diameters (d = 2.00, 2.38 and 3.17 mm) was investigated experimentally. Experiments were carried out with laminar air flow at steady-state. The friction factors, permeabilities, inertial and Ergun coefficients were determined for spiral packed beds. It was observed that the coefficients of the Ergun correlation were not suitable for the spiral packed beds. These coefficients were determined for spiral packed beds. In addition, considering the effect of the curvature ratio, a modified Dean number was defined. The relation between the pressure drop in spiral packed beds and the modified Dean number was presented. The effect of curvature ratio on pressure drop in spiral packed beds was investigated. The pressure drop correlation based on Re-p and modified Dean numbers obtained from all experimental data was presented and compared with the Ergun equation. This study will be a pioneering study in terms of the effects of the porous medium on the spiral channel.