The crop will be harvested from a total of 1,209,901 hectares, the statistics office said in a statement. The average yield is seen at 5.3 tonnes per hectare.
Last month the statistics office said that Serbia expected to raise its maize output by 7.54% to 6.62 million tonnes this year.
This year's expected maize output is 18.2% higher than the annual average harvest in the 1999-2008 period, the statement said.
The office also said the sunflower seed crop could drop by 16.6% to 379,004 tonnes this year. The soybean harvest is seen increasing by 7.1% to 375,962 tonnes and the sugar beet crop rising by 23.5% to 2.84 million tonnes.
The office will issue final figures on the 2009 crops at the end of November.