Kingdom Monera includes bacteria and blue-green algae. These are the simplest of all living organisms (assuming Viruses are not considered alive). They are single-celled organisms with little organization to their cell structure. Unlike members of the other four kingdoms, they have no membrane-bound structure protecting their genetic material (i.e. they have no nucleus).

Cells belonging to the Monera kingdom reproduce by replicating their DNA and dividing into two separate cells.

The Monera are divided into two divisions: Bacteria and Archaea.