A farm level irrigation water management decision s upport system (DSS-IWM) was developed based on Soil Water Balance-Crop Yield Benefit (SWAB-CRYB) model,crop penology model,root growth model,crop yield respo nse function,soil parameters,weather data and irrigation manage ment strategies. The DSS-IWM needs four input data files related to crop,soil,climate and irrigation strategies. In D SS-IWM Penman-Monteith method was used to estimate crop water requirement considering daily crop coefficients. So il water balance was carried out to obtain actual c rop evapotranspiration (ETa),using linear root growth model. Actual crop yield was estimated with crop yield response models incorporating crop growth stages and response of water stress to each crop growth stage. Economic model was developed to estimate net benefits from farms. DSS-IWM enables the estimation of soil moisture in the root zone,actual evapotra nspiration and return flow to the groundwater due to irrigation in terms of deep percolation,crop yield and net benefits by simulating the different processes responsible for soil water balance in the root zone. The DSS-IWM can be used for evaluation of effect of certain irrigation plan on crop yield reduction. A case stu dy of wheat crop irrigation water management by DSS -IWM showed its practical value and benefits. It could be an object ive oriented and practical irrigation water managem ent decision-making tool. https://www.ijiert.org/paper-details?paper_id=140555