Anemia is a medical condition in which the number of red blood cells or the hemoglobin is less than normal. Normal hemoglobin levels in adolescent girls is > 12 g/dl. Adolescent girls are said to be anemic if Hb <12 g/dl. The high number of worm infection and the high incidence of anemia among adolescent girls are closely related because worm infection is one of the causes of anemia. This study aimed to analyze factors affecting anemia among high school adolescent girls in the city of Palu. This study was an observational study with case-control study design. Stool sample tested by using direct method showed that 8 out of 72 samples (11.11%) were found positively infected by the worm eggs. There was no association between anemia and worm infection. Most respondents consumed insufficient daily intake of iron and vitamin C. Type of worms was mostly hookworm and follwed by Trihuris trichiura. In order to improve insufficient nutrient intake to prevent anemia in adolescent girls, there should be a communication between teachers and parents to get them more concerned about consuming varied and iron-rich foods, and preventing worm infection.