Recently many large scale computer systems are built in order to meet the high storage and processing demands of compute and data-intensive applications. MapReduce is one of the most popular programming models designed to support the development of such applications. It was initially created by Google for simplifying the development of large scale web search applications in data centers and has been proposed to form the basis of a ‘Data center computer’ This paper presents a realization of MapReduce for .NET-based data centers, including the programming model and the runtime system. The design and implementation of MapReduce.NET are described and its performance evaluation is presented.