Earthworms as critical components of natural communities have traditionally attracted the attention of researchers from various fields of biology and agriculture. From the observations of ancient times and up to our time, the research of earthworms has kept its relevance. One of the most interesting tasks has been the creation of an ecological classification of earthworms and its subsequent use. The purpose of this review is to consider various approaches to identifying ecological groups of earthworms (Oligochaeta, Lumbricidae) and the application of these approaches in scientific research. The article reviews the main types of Russian and world ecological classifications of earthworms and some recent additions to these classifications. Particular attention is paid to scientific research with different approaches to the study of ecological groups of earthworms.