Bed bugs, Cimex lectularius Linnaeus, are increasingly reported as pests in hotels, apartments and homes worldwide. Although limited ultrastructural analysis of bed bug nymphs and adults has been performed, little is known about the ultrastructure of bed bug eggs. This study, using scanning and transmission electron microscropy, revealed several unique structural aspects of bed bug eggs. Chorionic projections form a polygonal pattern covering the egg surface. A complex operculumcollar structure is found on the anterior end of the egg, and the inner surface of the collar has three distinct regions, a smooth outer rim, a porous palisade layer and a porous ribbed layer. The outer surface of the collar is smooth with an operculum fitting into the collar. Large and distinctly ridged polygons cover the surface of the operculum. The polygons around the perimeter of the operculum have a rugose surface; the polygons adjacent to the rugose ones display spheres on the surface; and the remaining polygons have a smooth surface. The lateral margin of the operculum has a porous rugose surface with ridges and the ventral inner surface is smooth. Internally, the chorion is made up of three distinct divisions, the outer electron-dense layer with round electron opaque areas near the surface, a middle layer which is less electron-dense and the innermost layer of porous struts creating distinct spaces. Three distinct layers are found in the operculum, an outer porous layer, then an electron-dense layer, and an inner layer of porous struts and spaces. These findings constitute the first detailed description of the bed bug egg using electron microscopy.