Nymphs and adults of the bed bug, Cimex lectularius L,. have compound eyes located on protrusions from the lateral area of the head. In this study, nine specimens from each nymphal instar, and ten adult males and females were examined by scanning electron microscopy to count and measure the ommatidia through the various developmental stages. Ommatidia making up the nymphal and adult eye were found to be round-to-oval and strongly convex. Numbers of ommatidia in the compound eye differed significantly between each nymphal instar and adults of both sexes; however, there was no significant difference in number of ommatidia between females and males. Ommatidial diameter in the first three instars ranged from 24.10 µm to 28.55 µm, whereas this range was much greater in later instars and adults, 20.35 µm – 30.15 µm. Diameters of the largest ommatidia ranged from 29.80 µm to 30.15 µm, and this size range was found on all nymphal instars and adults. The surface of the ommatidia was found to be smooth and without inter-ommatidial setae. The 6.5x increase in number of ommatidia from nymphal instar one to the adult stage is distinctly less than that found in other members of the Hemiptera. A linear relationship exists between width of the pronotum and number of ommatidia found in each nymphal instar and adults.