Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinal dystrophy, intellectual disability, polydactyly, obesity and renal anomalies. In photoreceptors (PR), light sensation occurs in outer segments (OSs), which are specialized primary cilia. BBS1, the major BBS gene, is part of a protein complex called “BBSome”, which is involved in intracellular protein transport. However, the precise function of BBS1/BBSome in controlling trafficking of ciliary proteins in PRs remains unclear. To investigate the role of the BBSome in photoreceptors, we conducted a label free quantitative proteomic investigation on the protein contend of isolated adult mutant and control outer segments. We revealed that a Bbs1 KO results in the loss of the entire BBSome from OSs. Besides the loss of the BBSome we found an overall accumulation of non-outer segment proteins in the OS. A majority of these proteins were membrane-associated, supporting the role of BBS1/the BBSome in controlling ciliary transport of membrane-associated proteins.