For engineering consulting companies, it is a major issue for decision makers to effectively use their available manpower resource to accomplish given jobs in a specified time period. In this research we employ mathematic programming techniques to develop a mixed integer programming model, given available engineer resource, project/job demand and related constraints, to optimally solve medium or large manpower assignment problems, in order to help the decision maker effectively assign projects/jobs to engineers. To demonstrate the model application and to preliminarily test the model in practice, we perform a case study using real operating data from an engineering consulting company. The results show that the model could be useful reference in practice.