In this paper, we used the fuzzy set theory for modeling flexible constraints and uncertain data in nurse scheduling problems and proposed a fuzzy linear model for nurse rostering problems. The developed model can produce rosters that satisfy hospital objectives, ward requirements and staff preferences by satisfying their requests as much as possible. Fuzzy sets are used for modeling demands of personnel in each shift. The objective is to identify the optimum roster for nurses in order to complete the weekly roster with fuzzy constraints. This model is implemented for the data collected from Namazi Hospital (NH) of Shiraz, which is the largest hospital in the south of Iran. After modeling, this problem is solved by using Lingo software. Finally we compare the result of fuzzy rosters with goal programming rosters that we have previously modeled and with manual rosters that are produced by the head nurses of NH.