This species is distinguished from its congeners by the following set of characters: head pointed anteriorly and considerably flattened in dorso-ventral direction; dermal papillae on top and sides of head; large bony prickles under pectoral fins; long second dorsal fin (length of its base 40% SL); long pelvic fins reaching anus; incomplete trunk canal of seismosensory system with 25-27 pores, its end on vertical of last rays of anal fin; semicircular shape of genital papilla in males; all fins (including pelvic and anal) with dark spots. The new species differs from the closely related C. koshewnikowi in following features: abundance of melanophores on ventral side of body (vs. absence of melanophores); dermal papillae on upper and lateral parts of head (vs. absence of papillae and presence of dermal wrinkles); longer caudal peduncle (14.6±2.1 vs. 8.3±0.5% SL); large eye diameter (23.1±1.1 vs. 19.1±0.6% of head length); wider interorbital space (16.3±3.4 vs. 9.8±0.5% of head length). Cottus dorofeevi differs from another Eastern European species C. gratzianowi in following characters: branched rays in pectoral fin absent (vs. frequent presence in C. gratzianowi); gap absent and three pores in occipital commissure of lateral line system present (vs. presence of gap and four pores in C. gratzianowi); poorly developed lower lobes of mouth (vs. massive lobes in C. gratzianowi) (Ref. 132919).