A study of the rural population of the village of Belumbang, Province of Bali, Indonesia, has been conducted to assess the relationship between intensity of hookworm infection (hookworm egg count) and iron stores, hemoglobin level or hematocrit. There was a significant negative correlation between serum ferritin level and hookworm egg count. However no correlation was found between hookworm egg count and hemoglobin level or hematocrit. In a separate analysis the above correlation could be shown in male hosts but not in female hosts. It is concluded that hookworm infection, even in light infection, can interfere with iron stores, but in female hosts this effect might be masked by other factors.