The objective of this study was to determine the mechanical and viscoelastic properties of extruded cylindrical strands from biodegradable polymer blends and to verify the correlation of the blend properties with their capacity to form films in the blown extrusion process. The production of biodegradable films would only occur if the extruded strands showed adequate characteristics. The strands were produced by extrusion with blends containing starch, glycerol, and fatty acids (caproic, lauric, and stearic). These blends were compared with a standard formulation containing poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer. From the mechanical tension tests, the extruded strands containing fatty acids differed significantly from the standard one, it was not clear the possibility to establish a comparison between the mechanical properties of the extruded strands and the formation of films. The rheological tests indicated that the polymer blends presented the desired viscoelastic characteristics for the film formation by blown extrusion. POLYM. ENG. SCI., 2012. (C) 2011 Society of Plastics Engineers