Congenital disorders of glycosylation (CDGs) are a group of inherited metabolic disorders that are caused by recessive mutations in genes required for glycoconjugate synthesis. More than 80% of the 100 distinct forms of CDG that have been identified cause severe neurological impairment, but it is unclear how defective glycosylation causes the neuropathology of CDGs. The eight-subunit conserved oligomeric golgi (COG) complex is required for the tethering of vesicles carrying glycosylation enzymes across the Golgi cisternae, and it has been proposed that the complex acts as a protein interaction hub, orchestrating retrograde Golgi traffic. On page 3637, Anna Frappaolo, Stefano Sechi, Tadahiro Kumagai and colleagues describe a Drosophila COG7-CDG model, and examine the effects of Cog7 deficiency in flies. The authors show that loss-of-function Cog7 mutations reduce lifespan and cause severe postural and movement deficits, similar to those displayed by COG7-CDG patients. Loss of Cog7 also results in decreased bouton numbers at the larval neuromuscular junction. Cog7 mutant flies show alterations in N-linked glycoprotein glycosylation, which is consistent with a role for Cog7 protein in N-glycosylation at the Golgi membranes. Moreover, the authors show that the COG complex cooperates with Rab1 and Golgi phosphoprotein 3 to regulate Golgi trafficking, and that overexpression of Rab1 can rescue the cytokinesis and locomotor defects associated with loss of Cog7. These data suggest that the Drosophila Cog7 disease model can be used to further investigate the pathophysiology of COG-CDGs.