The family Cimicidae includes bedbugs, of which two common species feed on humans. Cimex lectularius is widely distributed in tropical and non-tropical countries while C. hemipterus, commonly called the tropical bedbug, is essentially a species of the Old and New World tropics although it can also occur in warm areas of some non-tropical countries, such as in Florida, USA. It is not easy to separate these two species, but in C. lectularius the prothorax is generally 2.5 times as wide as long, whereas in C. hemipterus it is only about twice as wide as long. Also, the abdomen is more rounded in C. lectularius than in C. hemipterus.

A third species, Leptocimex boueti, is found mainly in West Africa but has also been recorded in South America. This species bites bats and also people, but is much less important as a pest than the Cimex species.

Infestations of bedbugs have increased since the 1990s in many countries, possibly due to increased global travel. For instance, after the 2000 Olympic Games nearly every hotel in Sydney was infested with bedbugs. Other factors include insecticide resistance and warmer houses. Bedbugs are not considered important vectors, but in addition to constituting a biting nuisance they have been reported as causing iron deficiency in infants.