Five strains of Gibberella fujikuroi and one of Fusarium moniliforme were screened for the production of gibberellic acid (GA(3)) in coffee husk, and based on the results, one strain, G. fujikuroi LPB-06, was selected. The comparative production of GA(3) by solid-state fermentation and submerged fermentation indicated better productivity with the former technique, mainly with pretreated substrate. The GA(3) accumulation was 6.1 times higher in the case of solid-state fermentation. Considering the C:N relation, higher yields of GA(3) were achieved using a mixed substrate comprising coffee husk and cassava bagasse (7:3, dry wt), increasing the results twice. Supplementation of an optimized saline solution containing 0.03% FeSO4 and 0.01% (NH4)(2)SO4 enhanced the accumulation of GA(3) 1.7 times in the fermented substrate. Under the finally optimized condition, the culture gave a maximum of 492.5 mg of GA(3)/kg of dry substrate, with a pH of 5.3, moisture of 75%, and incubation temperature of 29degreesC. GA(3) yield was almost 13 times more than the initial results.