The kinetics of beta -fructofuranosidase (Ffase) production by Aspergillus niger in submerged (SmF) and solid-state fermentation (SSF) systems was investigated. The maximum productivity of Ffase (81.8 U/litre/h) was obtained in SSF for 72 h while it was 18.3 U/litre/h in SmF for 120 h. The productivity of extra cellular Ffase produced in SSF was five-fold higher than in SmF. Optimization of fermentation medium for Ffase production was carried out using De Meo's fractional factorial design with seven components such as (NH4)(2)SO4, KH2PO4, FeSO4, MgSO4 . 7H(2)O, sucrose, area and yeast extract. The media designed for SmF after two steps of optimization supported the growth of A. niger and higher productivity of Ffase (58.3 U/litre/h) than with the medium before optimization. The optimized medium of SmF when used in SSF, did not improve the Ffase productivity and therefore the medium for SSF was optimized independent of SmF. After two optimization steps, the media was defined for SSF which supported the growth and high level of Ffase productivity (149.1 U/litre/h) in SSF compared to the medium before optimization (81.8 U/litre/h) and optimized medium for SmF (58.3 U/litre/h), The results suggested that the optimized media for SmF and SSF for the production of Ffase have to be different.