1. Three strains ofAspergilli having good PG activity were isolated. 2. The conditions for maximum elaboration of PG were studied using synthetic liquid media as well as wheat bran. (i) The enzyme content was maximum after 4 days of growth; pH below 5 favoured the formation of enzyme. (ii) Wheat bran was a better substrate than synthetic liquid media; aqueous glycerine was very satisfactory for extraction of the enzyme from wheat bran medium. 3. Partially purified PG preparations were obtained by precipitating enzyme at 60 per cent. concentration of ammonium sulphate after discarding the precipitate at 20 per cent. salt concentration; alcohol inactivated the enzyme to a great extent. 4. The optimum pH for activity with citrus pectin as substrate was about 4–5; hydrolysis was rapid during first 12–24 hours and decreased thereafter during a further 8–10 days period.