Giardiasis is still regularly encountered in the United States, both as endemic cases from the local community as well as in patients returning from travel abroad. Giardiasis should be suspected in any child with steatorrhea, unexplained chronic diarrhea (especially if associated with growth failure), weight loss, or abdominal pain and bloating. Duodenal aspiration or small intestinal biopsy may be necessary to make a diagnosis because Giardia lamblia are not found by stool examination in 50% of symptomatic individuals. A diagnosis of giardiasis is important because the disease is curable.