Three-dimensional convection of air in a vertical cylinder isothermally heated and cooled from a side wall was numerically computed both in magnetic and gravity fields. A single electric coil was placed around a cylinder to generate a magnetic field. Convection was calculated for various coil levels and magnetic strengths. The gravity field, magnetic strength and Rayleigh number are shown to have substantial effect. Convection modes and heat transfer rates are also presented. (c) 2005 Elsevier Ltd. All rights reserved.