This paper analyses the flow and heat transfer characteristics of laminar free convection in the boundary layer flow of micropolar fluids about a line heat source embedded on the edge of a plate. The nonlinear formulation governing equations are initially cast into dimensionless form by a local non-similar transformation and the resulting system of equations is then solved by the cubic spline collocation method and the finite difference scheme. Of particular interest are the effects of the micropolar parameter, Delta, and the Prandtl number on the velocity and temperature fields and on the skin friction coefficient, wall couple stress, and wall temperature. Numerical results are obtained for the velocity and temperature profiles for different values of the Prandtl number and micropolar parameter. (c) 2006 Elsevier Ltd. All rights reserved.