microRNAs (miRNAs) are small RNAs that play key roles in regulation of cellular processes and therefore could largely contribute to solving many problems in medicine, biotechnology, and other biological sciences. As a result, the numbers of research projects and publications on miRNAs are constantly growing, which is accompanied by increasing amounts of new data and databases need to be created for data storage. There are 51 dedicated miRNA databases at the moment, what make it quite difficult for the users to find relevant data. Moreover, such problems as insufficient documentation, low quality of data or flaws in the graphical interface make the things even worse. However, there are positive signs, including standardization of database interfaces, a tendency to create integrated systems that collect data from a number of databases and present it in a uniform format, and emergence of systems for automated data search and download.