Abstract: Proteomic approaches are currently used to explore and identify interacting partners of proteins involved in diverse biological processes or with therapeutic potential. The cannabinoid receptor 1, CB1, is the main mediator of cannabinoids effects in the central nervous system. The role of the endocannabinoid system in development and physiology and as a target of pharmacological and cellular therapies is the subject of intense research. Therefore, the scarcity of proteomic studies on the interactome of CB1 is, somehow, surprising (Mattheus et al., 2016). We addressed the proteomic study of the CB1 receptor interactome in rat primary cortical neuron cultures after immunoprecipitation (IP) of the receptor, but were puzzled by the confusing and disparate data regarding the identification of the CB1 receptor by western blot (WB). Therefore, we established handling conditions for IP and WB detection of CB1 that resulted in the consistent and specific detection and immunopreciptitation of CB1 with different antibodies. Based on WB results after deglycosylation and IP of the CB1 receptor performed with different antibodies, we propose a new interpretation of the molecular identity of CB1 multiple apparent molecular weights reported in the literature (Esteban et al., 2020). We believe our findings may contribute to clarify the identification of the receptor by WB and IP and make proteomic studies more solid and robust. The reinterpretation of WB and IP results discussed in our report may open new lines of research which will contribute to the understanding of the molecular nature of the CB1 receptor.