The thermal reaction between H and HCO was studied by classical trajectory calculations on an ab initio potential. The formation of H-2 + CO, the exchange of hydrogen atoms, and nonreactive encounters, proceeding either via direct or via complex-forming pathways, were separated. The reaction H + HCO -> H-2 + CO, with direct and complex-forming components, was found to have a low-pressure rate coefficient of 2.0(+/- 0.15) x 10(-10) cm(3) molecule(-1) s(-1), being nearly independent of temperature between 200 and 1000 K. This value is in agreement with the recent experimental value of 1.83(+/- 0.4) x 10(-10) cm(3) molecule(-1) s(-1). Thermal lifetime distributions of H2CO* complexes formed in the reaction are only weakly temperature dependent due to a compensation of energy and angular momentum effects.