Sacred architecture has been especially important in the development of each epoch's most important innovations and as a reflection of the main stylistic tendencies. Although over the last years interest in the heritage of sacred architecture in Latvia has resulted in several extensive publications, the subject still features the blind spot of the Art Nouveau influences upon the sacred architecture and décor in Latvia at the turn of the 20th century. Active construction of churches went on in this period, revealing stylistic pluralism in wide-range reconstruction and renovation of churches as well. The aim of this publication is to specify particular aspects of stylistic estimation related to Riga architecture in the late 19th and early 20th century. The influence of Art Nouveau upon Riga architecture was not homogenous; it did not appear an all-embracing style that is especially evident in public buildings, including industrial objects, educational and commercial institutions and their decorative handling. In a similar vein, church construction reflected a wide scope of historical styles - Art Nouveau has not left a considerable impact on churches of various confessions (12 in total) built in Riga and its surroundings around the turn of the 20th century. Still new spatial tasks had to be solved; in other cases Art Nouveau has inspired particular decorative elements.