A filariasis survey was conducted in Saukorem and Wefiani, Manokwari Regency, Irian Jaya, Indonesia, in October 1982. A total of 366 persons in Sau korem and 228 persons in Wefiani was examined. The infection rates of persons in these two surveyed areas were 20.5% and 20.6% and the intensity of infection were 18.75 and 14.79 respectively. The youngest found infected was an eight months old boy. The prevalence of microfilaraemia tended to increase with age and the prevalence in male was higher than female. The highest count of microfilariae was 659 per 20 mm3 blood sample. All microfilariae were identified as nocturnally periodic Wuchereria ban crofti with the periodicity index of 103.09.Twelve persons were found with symptoms of elephantiasis of legs, 3 persons with elephantiasis of legs and arms, 5 persons with elephantiasis of scrotum and one person with elephantiasis of legs and scrotum. The only mosquito vector identified in the surveyed area was Anopheles farauti.