Abstract : The study's main objective is to estimate and analyze the cost function of coffee production in the Jazan region. The study relied mainly on primary data obtained through a questionnaire and the personal interview of the selected sample of coffee farmers. The cost functions of coffee in the short and long run were estimated. The study results showed that the value of cost elasticity is less than one in the short and long run, which indicates that when production increases, costs decrease, meaning that economies of scale are present and production needs to be increased to reach a minimum efficient scale. The profit-maximizing production volume was greater than the actual production volume of the respondents. This indicates that there is an opportunity to increase production until it reaches optimum production. The study recommends supporting coffee farmers through the provision of improved seedlings, and the reclamation of mountain terraces to increase cultivated area, and the improvement of an irrigation system by solving the problem of access to water sources.