Malaria continues to be one of the most prevalent human infectious diseases. It is caused by protozoan para- sites of the Plasmodium genus that are transmitted from person to person by the bite of an infected female Anopheles mosquito. Studies of malaria epidemiology have traditionally used the microscope to measure the prevalence of infection within the human population and density of parasites within each human host. This method allows the distinction between species but not individuals within a species. Now there is unlimited access to a complete genome sequence for P. falciparum and several other genomes are almost complete. This genome information has allowed malariologists to examine the molecular epidemiology of malaria us- ing a variety of polymorphic genetic markers. Consequently, pictures are emerging of the genomic diversity, evolution and population genetics of malaria parasites. This review is an account of these studies and their impact on malaria epidemiology.