The article examines the chemical composition of the waters of mud volcanoes in Azerbaijan. It is based on the results of analyses of 65 water samples from the author's collection, as well as material from literary and fund sources. The mineralization of the waters of mud volcanoes in Azerbaijan varies widely from 5.8 to 84.7 g / l. In the distribution of mineralization of the waters of mud volcanoes by area (Fig. 1), a fairly regular increase in the lower direction is noted from 5.8-8.6 g / l in the northern part of the region to 40-80 g / l in the southern part (Khidirly, Duzdag, Neftchala, Yenikyshlak and others). In the latitudinal direction, the nature of the distribution of mineralization of the volcano waters is quite complex. The highest mineralization, more than 20 g / l, is characteristic of the waters of mud volcanoes located in the coastal strip: Shishikan, Kotyrlyg, B. Kenizdag, Kirdag, Dashgil, Bakhar, Agzybar and others. To the west and east (in the area of the Baku archipelago) the mineralization of the waters of mud volca-noes decreases to 12-13 g / l.