The present invention relates to the production of adeno-associated viral vectors in insect cells. The insect cells therefore comprise a first nucleotide sequence encoding the adeno-associated virus (AAV) capsid proteins, whereby the initiation codon for translation of the AAV VP1 capsid protein is an AUG. Upstream of the VP1 open reading frame an alternative out of frame start codon is placed such that translation initiation of the VP1 protein is modified, i.e. reduced, to allow production of VP1:VP2:VP3 in a good stoichiometry resulting in AAV with high potency.