In this study, the oviposition behavior of Ranatra linearis (Linnaeus, 1758) (Heteroptera: Nepidae), a predatory water bug, recorded for the first time in Kırıkkale province, and the morphological structure of the egg and respiratory horns of the species were investigated using electron, stereo and light microscopy. In addition, the water quality of its habitat was determined. R. linearis specimens live in good quality water. Female R. linearis specimens lay their eggs singly, close to each other and vertically on the substrate with their respiratory horns facing upwards. The eggs of R. linearis are nearly elliptical, approximately 2.91–3.32 mm long (excluding respiratory horns) and 0.8–0.99 mm wide. Mature eggs are light yellowish, darkening with age. Two respiratory horns, 3.29–4.85 mm long, are present on the anterior part of the shell. There are many circular aeropores in specialized areas at the tips of the horns. These pores are found near the tips of about 1/2 of the horns. The chorion is generally patterned with irregular reticulation. The exochorion is external, the endochorion with its vitelline envelope is internal, and the intrachorionic air space between them constitutes the chorion. The vitellus is present in the center of the egg. Determining some characteristics of the habitat of this species, which has great ecological importance, and clearly revealing the egg stage that will ensure the continuity of the species will contribute to biodiversity and will also make a significant contribution to studies to be carried out for ecological and biocontrol purposes.