This book constitutes the refereed proceedings of the 34th InternationalConference on Computer Safety, Reliability, and Security, SAFECOMP 2015, held inDelft, The Netherlands, in September 2014. The 32 revised full papers presentedtogether with 3 invited talks were carefully reviewed andselected from 104 submissions. The papers are organized in topical sections onflight systems, automotive embedded systems, automotive software, error detection, medical safety cases, medical systems, architecture and testing, safety cases, security attacks, cyber security and integration, and programming and compiling.