In 1764, Orfelin came to Dimitrios Theodosios's publishing house in Venice, where he spent the next six years before moving back to Karlovci. Theodosios, who began to print Serbian books in Venice in 1758, needed Orfelin to edit and proofread the abundant material being brought to him. Theodosios remained the only outlet for Serbian literature and printed books in Russo-Slavonic until the emergence of Kurtbek's publishing house in Vienna in 1770. Orfelin's editorial work gave a special impetus to the success of this Slavic publishing house. In a span of a few years many important books – "Catechisis" by Peter Mohyla and another "Catechisis" by Jovan Rajić, "Srbljak" (a compedium of old Serbian writings) and "Short Stories" by Feofan Prokopovich – were published there. Many of the books published were either translated or edited by Orfelin himself. He also published his own, original works, including "A Melody for the Spring" and "A Historical Poem" in 1765, "Latin Alphabet" in 1767, and "Latin Grammar" and "Slavic Alphabet" in 1768. A large number of the books printed in Theodosios's shop in Venice were purposefully mislabelled as printed in either Moscow or Sankt Petersburg publishing houses. The reasoning behind it was that Serbs under the Austrian rule had more faith in books published in Russia than in the West. While still in Venice, Orfelin also printed one of the most important copper engravings, "St. George with the Image of the Monastery of Sendjuradj" (1767), and the first one that he signed as a member of the Imperial Engraving Academy founded by Austrian Jacob Schmutzer.