In order to study the effectiveness of irrigation on Sudan grass fresh forage yield an irrigation water use efficiency (Iwue) and evapotranspiration water use efficiency (ETwue) were determined. A field experiment was conducted on the calcareous chernozem soil in the Vojvodina region, a northern part of the Serbia Republic, during 2005 and 2006 growing season. The experiment was arranged in a randomized complete block design and adapted to conditions of sprinkling irrigation. The trial included irrigated treatment (I - 60-65% of field water capacity - FWC) and a treatment without irrigation (Io). On average, irrigation did not significantly affect the fresh forage yield of Sudan grass (108.893 t ha-1 - 103.314 t ha-1) as the study period had precipitation higher than the long-term seasonal average. Evapotranspiration water use efficiency of Sudan grass, in irrigation conditions (ETm Iwue) ranged from 19.0 to 20.9 kg m-3 with an average value of 20.0 kg m-3, while evapotranspiration water use efficiency in conditions without irrigation (ETa Iwue) varied from 18.1 to 25.4 kg m-3 with an average value of 21.8 kg m-3. Irrigation water use efficiency (Iwue) varied from 2.8 to 3.7 kg m-3 with an average value of 3.2 kg m-3. Effect of irrigation on yield of Sudan grass and results of both ETwue and Iwue which were similar to those obtained from the literature indicate that irrigation schedule of Sudan grass in the study period was properly adapted to plant water requirements and water-physical soil properties. Determined values of ETwue and Iwue could be used for the planning, design and operation of irrigation systems, as well as for improving the production technology of Sudan grass in the region.