Citric acid is in high demand due to its low toxicity when compared to other acidulants commonly used in the food and pharmaceutical industries.The current study aims to identify effective variables for producing citric acid via solid-state fermentation (SSF) from sugarcane bagasse medium using Aspergillus flavus. A local fungus strain of A. flavus was isolated from spoiled fruits from Mansoura markets, was tested for its ability to produce citric acid, and then was used for maximizing citric acid production using sugarcane bagasse which was collected as a residue of juice shops as a low-cost fermentable material with high sugar content using solid state fermentation process. ​The highest yield of citric acid (14.41 g citric / 100 g bagasse) was obtained after 7 days of incubation at 25⁰C with using bagasse medium with moisture ratio 1.0:3.0 (bagasse/solution), supplemented with 1% fructose and ammonium nitrate as carbon and nitrogen sources, respectively. Medium pH was adjusted at 6.0.