&NA;Small round cell tumors (SRCTs) are among the most common solid tumors of childhood. A systematic approach including clinical, routine histologic, immunohistologic, electron microscopic, and/or molecular pathologic studies is essential to arrive at the precise diagnosis that determines the selection of specific therapeutic protocol for each particular case. This article describes the proper triage of the biopsy specimen and the characteristic and diagnostic features of the SRCTs in the basic conventional spectrum. It is inadvisable to rely on a single feature for diagnosis, and every attempt should be made to demonstrate more than one characteristic/diagnostic feature in every case. The nature of tumor cells of an SRCT should be demonstrated by objective criteria such as immunohistologic, ultrastructural, and/or molecular pathologic features.