On his return from Europe, Peretyatkovich designed his first major project - Solodovnikov's Cheap Apartment Building in Moscow (it was executed by Traugott Bardt), a typical "Northern Moderne", Saint Petersburg version of Art Nouveau. His second project - the Northern Insurance Buildings in Moscow, was executed in collaboration with Ivan Rerberg and Vyacheslav Oltarzhevsky in stern Neoclassical Revival. This buildings are also notable as Ilya Golosov's first employment and for Sergei Rachmaninoff melody written for the chiming clock. Now, they house the Constitutional Court of Russia.