This book constitutes revised selected papers from the 27th Argentine Congress on Computer Science, CACIC 2021, held in Salta, Argentina in October 2021. Due to the COVID-19 pandemic the conference was held in a virtual mode.  The 18 full papers and 3 short papers presented in this volume were carefully reviewed and selected from a total of 130 submissions. They were organized in topical sections named: intelligent agents and systems; distributed and parallel processing; computer technology applied to education; graphic computation, images and visualization; software engineering; databases and data mining; hardware architectures, networks, and operating systems; innovation in software systems; signal processing and real-time systems; computer security; and digital governance and smart cities.