This paper presents data on the incidence and clinical spectrum of lymphadenopathy, then offers guidelines for clinical decision making in regard to this problem. Eighty cases were identified and reviewed, for an annual incidence of 0.5% in the study population. Most (70%) cases were discovered by patients themselves. Several clinical parameters important to the evaluation of lymphadenopathy were incompletely recorded in the medical record. Excepting node enlargement, few associated physical and laboratory findings were discovered. Isolated cervical nodes accounted for 44% of all cases while 24% of patients had enlarged nodes in more than one anatomic region. The most frequently performed laboratory test was the complete blood count (34%), and the most frequently positive test was the throat culture (30%). Twenty percent of patients received antibiotics. No cases of malignancy were discovered. A four-level model is proposed for clinical decision making in the investigation of lymphadenopathy. This takes into account: (1) knowledge of the problem's natural history, (2) key initial findings, (3) the value of time, and (4) costs and usefulness of laboratory studies.