Double-membrane autophagosomes sequester cytoplasmic material and target it for lysosomal degradation. Although more than 30 autophagy-related proteins (Atg) have been linked to the process in yeast, the origin of autophagosomal membranes has remained unclear. The sole multi-spanning transmembrane protein Atg9 labels cytoplasmic punctae and is required for autophagosome formation. Ohsumi and colleagues have used high temporal resolution fluorescence microscopy and single particle tracking, in combination with electron microscopy and biochemical characterization of Atg9-labelled vesicles, to investigate the role of Atg9 in autophagosome formation (J. Cell Biol. 198, 219–233; 2012). They observed that Atg9–GFP labels single-membrane vesicles that are highly motile in the cytoplasm. Using the photoconvertible tag Kaede, they showed that Atg9 vesicles are generated de novo following autophagy induction by starvation. The authors extended previous findings indicating that these vesicles emerge from the Golgi apparatus, and also implicated Atg23 and Atg27 in their formation. By employing atg mutants blocked at distinct steps of autophagosome formation, they demonstrated that Atg9 vesicles assemble into the pre-autophagosomal structure. Only few of these vesicles were sufficient to trigger formation of an autophagosome that contained Atg9 on its outer membrane. It is thus likely that further sources of lipids are used for autophagosomal growth.