These sporozoites move into the bloodstream and infect cells in the host liver, where they grow and divide over the course of approximately one week.

Occasionally, after infection of a red blood cell, the parasite develops into one of two distinct sexual forms called male and female gametocytes (also micro and macrogametocytes respectively).

[11] The zygote develops into a motile stage called the ookinete which penetrates the wall of the mosquito gut and forms a stationary oocyst.

[11][12] The effect of infection on primate hosts has primarily been studied in rhesus monkeys, where P. cynomolgi generally causes mild and self-limiting illness.

[11] The exception to this is in pregnant monkeys, where P. cynomolgi infection can be severe, resulting in death of the mother and fetus without antimalarial treatment.

[11] Plasmodiumcynomolgi is in the genus Plasmodium, which contains all Apicomplexan parasites that undergo asexual reproduction through schizogony and digest red blood cell hemoglobin to produce the crystalline pigment hemozoin.

[15][10] Due to this, P. cynomolgi has been used in research on a broad variety of malaria topics including hypnozoite biology, host immune responses to infection, and to test the efficacy of antimalarial drugs and vaccines.