This book constitutes the refereed proceedings of the 27th International Conference on Information and Software Technologies, ICIST 2021, held in Kaunas, Lithuania, in October 2021.

The 24 full papers and 6 short papers presented were carefully reviewed and selected from 79 submissions. The papers discuss such topics as ​business intelligence for information and software systems, intelligent methods for data analysis and computer aided software engineering, information technology applications, smart e-learning technologies and applications, language technologies.