It has been suggested that Plasmodia manipulate their vertebrate hosts to enhance parasite transmission. Using a dual-choice olfactometer, we investigated the attraction of Anopheles gambiae to 50 Kenyan children (aged 5–12 years) who were naturally infected with Plasmodium falciparum or non-infected controls. Microscopic gametocyte carriers attracted almost 2 times more mosquitoes than children who were parasite free, harboured asexual stages, or had gametocytes at submicroscopic densities. By using highly sensitive stage-specific molecular methods to detect P. falciparum, we show that gametocytes and not their non-infectious asexual progenitors—induce increased attractiveness of humans to mosquitoes. Our findings therefore support the parasite host manipulation hypothesis.