  In this paper, we present a database of class I methanol masers. The compiled
information from the available literature provides an open and fast access to
the data on class I methanol maser emission, including search, analysis and
visualization of the extensive maser data set. There is information on
individual maser components detected with single-dish observations and maser
spots obtained from interferometric data. At the moment the database contains
information from ~100 papers, i.e. ~7500 observations and ~650 sites of class I
methanol masers. Analysis of the data collected in the database shows that the
distribution of class I methanol maser sources is similar to that of class II
methanol masers. They are mostly found in the Molecular Ring, where majority of
the OB stars are located. The difference between class I and II distributions
is the presence of many class I methanol masers in the Nuclear Disk region
(Central Molecular Zone). Access to the class I methanol maser database is
available online at http://maserdb.net
