Some individuals have reported various symptoms that they have intuitively associated with infrasound from wind turbines. Scientific evidence on the potential association or studies focusing directly on the health effects of wind turbine infrasound are lacking. This research project aimed at assessing whether wind turbine infrasound has harmful effects on human health. A questionnaire study, sound measurements, and provocation experiments were conducted. In the questionnaire study, symptoms intuitively associated with wind turbine infrasound were relatively common within 2.5 km from the closest wind turbine and symptom spectrum was broad. Many of the symptomatic respondents associated their symptoms also with vibration or electromagnetic field from wind turbines. In measurements, infrasound levels were similar to the levels occurring typically in urban environments. The captured sound samples with the highest infrasound levels and amplitude modulation values were used in the double blinded provocation experiments. The participants who had previously reported wind turbine infrasound related symptoms were not able to perceive infrasound in the noise samples and did not find samples with infrasound more annoying than those without previous wind turbine infrasound related symptoms. Further, wind turbine infrasound exposure did not cause physiological responses in either participant group.