The two volumes LNCS 8805 and 8806 constitute the thoroughly refereed post-conference proceedings of 18 workshops held at the 20th International Conference on Parallel Computing, Euro-Par 2014, in Porto, Portugal, in August 2014. The 100 revised full papers presented were carefully reviewed and selected from 173 submissions. The volumes include papers from the following workshops: APCI&E (First Workshop on Applications of Parallel Computation in Industry and Engineering – Big Data Cloud (Third Workshop on Big Data Management in Clouds) – DIHC (Second Workshop on Dependability and Interoperability in Heterogeneous Clouds) – Fed ICI (Second Workshop on Federative and Interoperable Cloud Infrastructures) – Hetero Par (12th International Workshop on Algorithms, Models and Tools for Parallel Computing on Heterogeneous Platforms) – Hi BB (5th Workshop on High Performance Bioinformatics and Biomedicine) – LSDVE (Second Workshop on Large Scale Distributed Virtual Environments on Clouds and P2P) – Mu Co Co S (7th International Workshop on Multi-/Many-core Computing Systems) – OMHI (Third Workshop on On-chip Memory Hierarchies and Interconnects) – PADAPS (Second Workshop on Parallel and Distributed Agent-Based Simulations) – PROPER (7th Workshop on Productivity and Performance) – Resilience (7th Workshop on Resiliency in High Performance Computing with Clusters, Clouds, and Grids) – REPPAR (First International Workshop on Reproducibility in Parallel Computing) – ROME (Second Workshop on Runtime and Operating Systems for the Many Core Era) – SPPEXA (Workshop on Software for Exascale Computing) – TASUS (First Workshop on Techniques and Applications for Sustainable Ultrascale Computing Systems) – UCHPC (7th Workshop on Un Conventional High Performance Computing) and VHPC (9th Workshop on Virtualization in High-Performance Cloud Computing.