"Aufwuchs" production was measured from its accrual on plexiglass substrates submerged in a stream. A method was developed for separating autotrophic and heterotrophic "aufwuchs" production and for separating this production from organic and inorganic sediments. The average "aufwuchs" production in the entire river during the summer of 1962 was 281.8 mg organic weight M-2 day-1, with the autotrophic organisms contributing 212.8 mg and the heterotrophic 69.0 mg.