The recently published Estonian Etymological Dictionary (EED) summarizes the research done on the origin of the word stems used in standard Estonian. The basis of the EED entry list are the stems found in the Estonian Orthological Dictionary “ÕS 2006”, with the exclusion of recent foreign stems. The given statistical overview of the stems of standard Estonian is based on the EED. In the article, a stem is defined in a narrower sense, also considering the language-historical aspect: a stem is a root morpheme carrying a lexical meaning, which does not contain any historical derivational suffixes and cannot be identified phonetically with any other root morpheme with a lexical meaning. The Estonian word stems can be divided into three big groups: native stems, borrowed stems and artficial stems. In the last 30 years (since Rätsep 1983) the classification of borrowed stems has been further specified in that Indo-European and Indo-Iranian stems are regarded as a separate layer, as are Germanic and Scandinavian ones. The number of established Baltic loans has grown essentially. However, the group of Estonian stems of unknown origin, not having any established equivalent, is still quite numerous. The possibly more distant origin of the stems with exclusively Finnic equivalents is also in need of additional research.