Abstract: In this paper, the nonlinear stability of double-diffusiveconvection with cross-diffusion in a thermohaline system is analyzed. Byusing a simple expression, the nonlinear equations are solved. Byexpressing two cross-diffusive coefficients by two parameters, a more generalR_T-R_S relation and expressions of steady finite amplitude areobtained. These expressions can be reduced to those previously-derived oneswhen both cross-diffusive coefficients are equal to zero.