Adhesive interactions in the retina instruct the developmental specification of inner retinal layers. However, potential roles of adhesion in the development and function of photoreceptor synapses remain incompletely understood. This contrasts with our understanding of synapse development in the central nervous system (CNS), which can be guided by select adhesion molecules such as the Synaptic Cell Adhesion Molecule 1 (SynCAM 1/CADM1/Nectin-like 2 protein). This immunoglobulin superfamily protein modulates the development and plasticity of classical excitatory synapses. We now show by immuno-electron microscopy and immunoblotting that SynCAM 1 is expressed on mouse rod photoreceptors and their terminals in the outer nuclear and plexiform layers (ONL and OPL) in a developmentally regulated manner. Expression of SynCAM 1 on rods is low in early postnatal stages (P3-P7), but increases after eye opening (P14). In support of functional roles in the photoreceptors, electroretinogram recordings demonstrate impaired responses to light stimulation in SynCAM 1 knockout (KO) mice. In addition, the structural integrity of synapses in the OPL requires SynCAM 1. Quantitative ultrastructural analysis of SynCAM 1 KO retina measured fewer fully assembled, triadic rod ribbon synapses. Further, rod synapse ribbons are shortened in KO mice and protein levels of Ribeye, a major structural component of ribbons, are reduced in SynCAM 1 KO retina. Together, our results implicate SynCAM 1 in the synaptic organization of the rod visual pathway and provide evidence for novel roles of synaptic adhesion in the structural and functional integrity of ribbon synapses.