The article introduces a novel approach to crystallize membrane proteins, specifically bacteriorhodopsin (BR), using lipidic cubic phases. These phases, composed of lipid, water, and protein in appropriate proportions, form a structured, transparent, and complex three-dimensional array with interconnected aqueous channels. This system provides nucleation sites and supports protein growth through lateral diffusion. The authors demonstrate that BR crystals can be obtained from bicontinuous cubic phases but not from micellar systems, highlighting the importance of the bilayer continuity for crystal growth. Hexagonal BR crystals diffracted to 3.7 Å resolution, with a space group P63 and unit cell dimensions of a = b = 62 Å, c = 108 Å. The study suggests that lipidic cubic phases offer a promising method for obtaining well-ordered three-dimensional crystals of membrane proteins suitable for X-ray analysis, with potential applications in high-resolution structural studies.The article introduces a novel approach to crystallize membrane proteins, specifically bacteriorhodopsin (BR), using lipidic cubic phases. These phases, composed of lipid, water, and protein in appropriate proportions, form a structured, transparent, and complex three-dimensional array with interconnected aqueous channels. This system provides nucleation sites and supports protein growth through lateral diffusion. The authors demonstrate that BR crystals can be obtained from bicontinuous cubic phases but not from micellar systems, highlighting the importance of the bilayer continuity for crystal growth. Hexagonal BR crystals diffracted to 3.7 Å resolution, with a space group P63 and unit cell dimensions of a = b = 62 Å, c = 108 Å. The study suggests that lipidic cubic phases offer a promising method for obtaining well-ordered three-dimensional crystals of membrane proteins suitable for X-ray analysis, with potential applications in high-resolution structural studies.