The classification of renal epithelial tumors has been an evolving process over many years. Through national/international consensus, renal tumors are now classified incorporating both morphologic and genetic characteristics. The Heidelberg classification of renal epithelial tumors published in 1997 was the first classification integrating molecular and genetic features as one of the diagnostic tools applicable to renal epithelial tumors. ¹ This classification was further corroborated by the so-called Union for International Cancer Control (UICC) Rochester Classification, ² which later evolved to the 2004 World Health Organization (WHO) Pathology and Genetics of Tumors of the Urinary System and Male Genital Organs, the 2012 Vancouver International Society of Urologic Pathology (ISUP) consensus conference, ³ the 2016 WHO Classification of Tumors of the Urinary System and Male Genital Organs, and recent publications on existing and emerging renal neoplasm by the Genitourinary Pathology Society (GUPS). ^4,5   However, with advances in molecular pathology rapidly changing, the classification of renal epithelial tumor is constantly evolving, permitting discussion in this atlas of unusual morphologic variants of well-established categories,⁴ as well as additional novel and provisional tumor entities. ⁵ For the purpose of uniformity, the latest 2022 WHO Urinary and Male Genital Tumours will be followed but adapted where appropriate for the Atlas. The major emphasis is placed on the genetic markers increasingly adopted in clinical practice to complement the role of histopathology in classification and prognostication.