This paper provides an evaluation of the secondary effects of a major irrigation and drainage project being implemented in the province of Sindh, Pakistan. To allow the empirical magnitude of these effects to be estimated a simple model of the regional economy was de~eloped. While this model reflects various resources and data constraints it incorporates the effects of all the major linkages in the local economy. It was found that the secondary effects of the project, once it is fully operational, will be quite large in relation to the direct benefits. This reflects the high degree of integration of agriculture with the local economy, through both backward and forward linkages.