This document is a thesis work which presents the expansion of an existing AUTOSAR compatible operating system from single-core to multicore architecture. To begin with, it investigates the basic requirements and specifications for this process. It is researching the standards and available documentation to aid the development. The document describes the appearing problems and challenges of a multicore system. The solutions provided by AUTOSAR OS v4.2 release are introduced and they are analyzed. New objects got implemented and existing implementation of the operating system was modified according to the standard. Multiple implementation concepts are described at these parts with their advantages and disadvantages. This document also provides analysis of these newly implemented objects. The operating system got ported to the TC27x microcontroller of the Aurix family. The implemented objects were analyzed and tested on the microcontroller. Finally the document demonstrates the completed system capabilities through an example project. The operating system used without the RTE layer so its functions are called directly from the application.