The earliest roach fossils are thought to come from the Carboniferous period more than 345 million years ago. Modern cockroaches are said to have evolved from these ancient insects. The first modern cockroach appeared during the early Cretaceous period.
There are more than 4,500 species of cockroaches on the planet, 30 of which are common to humans. It is now known that the cockroach was around long before the dinosaurs roamed the Earth. The first roaches were approximately 3.5 inches long and 1.5 inches wide, which is twice as big as the roaches in American homes.