A method for the in vivo production of 1,3-butadiene from 2,4-pentadienoate is described (FIG. 1). Enzymes capable of decarboxylating 2,4-pentadienoate to 1,3-butadiene have been discovered. Recombinant expression of these newly discovered enzymes has resulted in the engineering of microorganisms capable of producing 1,3-butadiene when cultured in the presence of 2,4-pentadienoate. 1,3-butadienoate is an important monomer used in the manufacturing of rubbers and plastics. This invention will help to enable the biological production of 1,3-butadiene from renewable resources such as sugar, for example.