Lectins are proteins capable of specifically recognizing and reversibly binding carbohydrates, but they lack enzymatic activity toward their bound molecules. Through this carbohydrate recognition, lectins play key roles in regulating physiological and defense processes in organisms. To obtain functionally active plant recombinant lectins, it is necessary to use expression systems that can provide correct post-translational modifications, including glycosylation, which is impossible when expressing proteins in bacterial cells. Transient expression of plant proteins in leaves enables the formation of a proper modification profile and ensures high reproducibility. This work presents an optimized protocol for obtaining recombinant flax lectins using the method of transient expression in Nicotiana benthamiana leaves. The protocol encompasses all stages, from primer design and molecular cloning to the production of purified protein and the subsequent assessment of N-glycosylation.