In an effort to better describe the incidence and characteristics of chronic giardiasis in an urban private practice outpatient setting, we reviewed our experience of 65 cases. In the entire group, the mean duration of symptoms was 1.9 years. A history of foreign travel was described by 45%. No association with homosexuality was noted. Chronic giardiasis, defined as that population symptomatic for six months or longer, constituted 58% of the entire group (38 cases). For these patients the mean duration of symptoms was 3.3 years. When compared to acute giardiasis, an increased frequency of constipation and upper gastrointestinal complaints was noted in the chronic population. Symptomatic cure was obtained in 71% of chronic cases and 93% of acute. Palliative results were noted in 18% of chronic cases and 4% of acute. We conclude that giardiasis is frequently a chronic disease in our population with symptoms lasting years. The incidence is similar in both sexes and a history of foreign travel is often absent. A disproportionate incidence in male homosexuals was not noted in our study.