Biological production of acrylic acid from cheese whey has been demonstrated. Lactose in sweet whey fortified with yeast extract was first converted to a stoichiometric mixture of propionic and acetic acids in 70 h by a coculture of Lactobacillus bulgaricus and Pro‐pionibacterium shermanii. Further conversion of propionate to acrylate was accomplished by resting cells of Clostridium propionicum in systems in which methylene blue acted as an electron acceptor. A maximum acrylate yield of 0.133 mmol/g of wet cell was achieved for periods of 6 h, after which resting cell activity declined substantially. Bio‐conversion of propionate to acrylate could also be carried out by cells immobilized in calcium alginate beads with no decrease in cell productivity or initial reaction rate.