A new method of determining pectinolytic activities was developed with the aid of dye‐substituted substrate. Soluble stained pectic acid proved to be the most suitable substrate for the agar diffusion, the cupplate and the inoculation test, especially for screening purposes. Insoluble stained pectic acid was used as an enzyme substrate in the photometric test. The sensitivity of the method of 2 × 10‐2μmol of reducing groups liberated per min per ml of enzyme may be considered satisfa