Markarian galaxies are the result of the First Byurakan Survey (FBS) conducted in 1965–1980 by B.E. Markarian et al. The sample consists of 1515 UV‐excess galaxies containing many active galaxies, both AGN and starburst (SB) galaxies that are interesting from the point of view of galaxy evolution and multiwavelength studies. Several catalogs of Markarian galaxies have been published; however, multiwavelength (MW) data were not provided and matched for more efficient investigations. Moreover, SDSS spectra now give possibility for better classification by activity types, and we have accomplished fine classification obtaining new types and subtypes for most of the objects. We have cross‐correlated the Markarian catalogue with all available large‐area MW catalogues at various wavelengths, from X‐ray to radio: ROSAT BSC and FSC, GALEX, APM, MAPS, USNO B1.0, GSC 2.3.2, SDSS, 2MASS PSC and ESC, WISE, AKARI‐IRC, IRAS PSC, FSC, and SSSC, AKARI‐FIS, GB6, NVSS, FIRST, SUMSS, WENSS, and 7C providing 35 photometric data‐points, as well as the Digitized FBS (DFBS, http://byurakan.phys.uniroma1.it/) and Hamburg Quasar Survey (HQS) low‐dispersion spectra. The Armenian Virtual Observatory (ArVO, http://www.aras.am/Arvo/arvo.htm) services have been used for crosscorrelations and extraction of DFBS spectra; MW SEDs have been built using the IVOA tools, and MW classification has been accomplished. Diagrams with MW flux ratios have been built to reveal objects with extreme characteristics. The classifications have been matched with these flux ratios. A MW catalog of Markarian galaxies has been compiled. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)