The esophageal glands are extremely large and are mainly outside of the esophagus, extending posteriad into the body cavity. Cervical papillae are present near the rear level of the nerve ring. Males have a conspicuous copulatory bursa, consisting of two broad lateral lobes and a smaller dorsal lobe, all supported by fleshy rays. The spicules are simple, needlelike, and similar. A gubernaculum is present.
Females have a simple, conical tail.
The vulva is postequatorial, and two ovaries are present. Necator americanus has a pair of dorsal and a pair of ventral cutting plates surrounding the anterior margin of the buccal capsule. In addition, a pair of subdorsal and a pair of subventral teeth are near the rear of the buccal capsule. Males are 7 to 9 mm long and have a bursa diagnostic for the genus. The needlelike spicules have minute barbs at their tips and are fused distally.