This paper will give an overview of multicore in automotive applications, covering the trends, benefits, challenges, and implementation scenarios.The automotive silicon industry has been building multicore and multiprocessor systems for a long time. The reasons for this choice have been: increased performance, safety redundancy, increased I/O & peripheral, access to multiple architectures (performance type e.g. DSP) and technologies. In the past, multiprocessors have been mainly considered as multi-die, multi-package with simple interconnection such as serial or parallel busses with possible shared memories. The new challenge is to implement a multicore, micro-processor that combines two or more independent processors into a single package, often a single integrated circuit (IC). The multicores allow a computing device to exhibit some form of thread-level parallelism (TLP).The automotive industry is also increasing complexity and safety with new standards such as IEC61508 and ISO 26262 being implemented. This will enable new systems X-by-wire. To achieve the certification, the electronic architecture will have to be modified to be SIL3 (safety integrity level) compliant. Dual-core is a good candidate with the possibilities of asymmetrical, symmetrical and lockstep configurations.Developing automotive applications is also bound by specific processes and development methodologies. It requires following guide-lines, recommendations, best-practices and standards e.g. AUTOSAR and OSEK.The amount of software that is built by auto-code generation may reach more than 50% in some applications. The use of multicore processors requires re-inventing tools: performance modeling, benchmarking of multiprocessor systems, automatic load-balancing, multiprocessor debugging and on chip instrumentation, calibration and fast prototyping.