Optimal allocation of water resources by using mathematical programming models has been considered in the recent years. Uncertainty is one of the important and fundamental factors in the modeling of these type of problems. The present study develops a model for optimal allocation of water in Nekooabad irrigation network in Esfahan province established in 2012- 2014. In order to considering the uncertainty, the Interval- Parameter Programming (IPP) and Two- Step Infinite ∝- Cuts Fuzzy Linear Programming (TSIFP) were used. The results showed that as increasing degree of conservatism against uncertainty (used of TSIFP instead of IPP), the middle bound of gross margin benefit reduced from 3724.5 to 3565 billion Rials (4.3 percent) for delivering water in the years of planning horizon. Finally, using the allocation model presented in TSIFP to approach the more protection of the system against losses, due to the lake of uncertainty for water availability, is recommended. To compensate loss of gross benefit of farmers in this recommended pattern, efficiency enhancement policies emphasized. Also, benefit of old structures of Nekooabad irrigation network in the area of Falavarjan and Najafabad, with the highest value of allocation of water, to reduce waste water in this network is recommended.