A joint optimization problem of pricing, marketing and production planning for a deteriorating item considering elastic demand is studied. A nonlinear programming model is developed to describe the problem. Since the model is highly nonlinear and cannot be solved directly, a solution approach based on geometric programming is proposed. In the approach, the joint optimization problem is first reduced to an unconstrained problem in a single variable. Then the resulting problem is solved by using the linear search algorithm of golden section. Finally, a numerical example verifies the operability and correctness of the proposed approach and the sensitivity analysis of key parameters is presented.