Mononuclear nickel(II) and copper(II) complexes with Schiff base ligands derived from benzoylacetone S-methylisothiosemicarbazone and 2,6-diformyl-4-methylphenol (CuL1 and NiL1) or 1-hydroxy-2-naphthaldehyde (CuL2 and NiL2) were previously synthesized and investigated.1, 2 The aim of this work was to investigate the influence of previously obtained complexes on the enzymatic activity of cellulases and xylanases synthesized by fungal strain Aspergillus niger CNMN FD 10. It was found that the introduction of CuL1 or NiL1 complexes in the culture medium of micromycetes Aspergillus niger CNMN FD 10 causes a slight increase in the activity of s̃-glucosidases (2.81 U/mL compared with 1.59 U/mL in the control) and endoglucanases (6.36 U/mL compared with 5.71 U/mL in the control) at complex concentration of 1 mg/L. In the case of CuL2 or NiL2 complexes a positive effect was observed, i. e. the maximum activity of the enzymes was observed 24 hours earlier and it was significantly higher than in the controls. The maximum activity of s̃-glucosidases was 22.5% higher than in the control. The maximum activity of xylanases was 31.2% and 35% higher than in the control. Endogluconase's maximum activity was with 27.7% and 28.4% higher than in the control.