The nonlinear kinetic aerosol equation, describing the time evolution of an aerosol distribution within a well-stirred container, is formulated in a mathematically "conservative" form. A numerical method is then developed for which conservation of mass is automatically satisfied. This procedure simplifies the derivation of conservative numerical schemes by reducing the number of approximations that must be made. Comparisons between an exact solution of the kinetic aerosol equation and numerical approximations show the following: numerical solutions based on the conservative form of the kinetic equation are more accurate and are obtained more efficiently than numerical solutions based on the standard "nonconservative" form of the kinetic equation.