The effect of nitriloacetic acid (NTA) and 8-hydroxyquinoline on the production of citric acid by Aspergillus niger was investigated. The complexing agents showed an effect only during inoculation of the microorganism. Subsequent addition after inoculation did not produce any significant increase in citric acid yield. When 200 ppm of NTA was added during inoculation, an increase of 10.9 g.dm(-3) citric acid over that produced by the control culture was observed. 8-Hydroxyquinoline, on the other hand, produced a higher concentration of citric acid which was 34 g.dm(-3) over that of the control culture. The use of 8-hydroxyquinoline is therefore suggested for the production of citric acid from molasses using Aspergillus niger.