This prospective study evaluated 382 pediatric patients with peripheral lymphadenopathy (LA) presenting at the Pediatric Oncology and Hematology Departments of Social Security Children's Hospital and Gazi University Medical Faculty Hospital. The ages of the patients ranged Between 2 months and 16 years (median 7 years); 72% of the patients were male. Of the 382 patients, 138 had localized LA (a single anatomic area involved), 171 had limited LA (two or three areas involved), and 73 had generalized LA (Sour or more anatomic areas involved). The specific etiology (either benign or malign) was defined in 79% of patients with generalized LA. However, in patients with localized LA and limited LA, specific etiology could be identified only in 43 and 53% of patients, respectively. Based on this study, BCG-LA and pyogenic infections are more frequently manifested by localized LA; LA of unknown origin, Hodgkin's disease, tuberculosis, nasopharyngeal carcinoma, and toxoplasmosis are frequently manifested by localized or limited LA; and cytomegalovirus infection (CMV), infectious mononucleous, rubella, acute leukemia, non-Hodgkin's lymphoma are frequently manifested by limited or generalized LA. Out of 382 patients, 196 patients had a maximum lymph node diameter of less than 2 cm. A benign etiology was shown in 159/196 of these patients. In 37/196 of these patients LA was due to a malignancy, and these cases almost invariably had some apparent additional diagnostic clinical and laboratory findings. Based on this observation a maximum lymph node size of 2 cm was considered an appropriate limit to distinguish malignant disease from benign causes except when there is other evidence of an underlying malignant disease. However, lymphadenopathies located at supraclavicular region (27 patients) either localized or as part of generalized LA had a specific benign or malignant disease in etiology (malignancy in 20, tuberculosis in 3, CMV in 2, sarcoidosis in 1, and lipoma in 1) even though they were less than 2 cm in diameter.