InternationalWorkshop on Blockchain and Distributed Ledgers: Technologies and Applications (BDLTA 2020) -- International Workshop on Bio and Neuro Inspired Computing and Applications (BIONCA 2020) -- International Workshop on Computer Aided Modeling, Simulation and Analysis (CAMSA 2020) -- InternationalWorkshop on Computational and Applied Statistics (CAS 2020) -- International Workshop on Computerized Evidence-based Decision Making (CEBDEM 2020) -- International Workshop on Computational Geometry and Applications (CGA 2020) -- International Workshop on Computational Mathematics, Statistics and Information Management (CMSIM 2020) -- International Workshop on Computational Optimization and Applications (COA 2020) -- International Workshop on Computational Astrochemistry (CompAstro 2020) -- International Workshop on Cities, Technologies and Planning (CTP 2020) -- International Workshop on Econometric and Multidimensional Evaluation in Urban Environment (EMEUE 2020).

The seven volumes LNCS 12249-12255 constitute the refereed proceedings of the 20th International Conference on Computational Science and Its Applications, ICCSA 2020, held in Cagliari, Italy, in July 2020. Due to COVID-19 pandemic the conference was organized in an online event. Computational Science is the main pillar of most of the present research, industrial and commercial applications, and plays a unique role in exploiting ICT innovative technologies. The 466 full papers and 32 short papers presented were carefully reviewed and selected from 1450 submissions. Apart from the general track, ICCSA 2020 also include 52 workshops, in various areas of computational sciences, ranging from computational science technologies, to specific areas of computational sciences, such as software engineering, security, machine learning and artificial intelligence, blockchain technologies, and of applications in many fields. .