We report a detailed study of the pollen wall structure in Linum burkartii and L. usitatissimum (Linaceae). This study was carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results confirm that the exine of the species studied is formed by: the ectexine constituted by clavae, gemmae, and a loose basal layer, a thin endexine and a fibrilar intine. These observations constitute the first report on the ultrastructure of pollen in the Linaceae that characterizes the species here studied and expands the palynological knowledge of this family.