The diverse range of military vehicles and operational conditions share a number of powertrain objectives including high fuel efficiency and fuel adaptability to lessen the logistical impact of conflict; low heat rejection to minimize the cooling system losses, vulnerability and powertrain package space; tractive power delivery to provide superior mobility for the vehicle; and light weight to allow for more armor to be used and/or payload to be carried. This paper first provides an overview of the operational powertrain requirements of military vehicles. A review the processes used to integrate powertrain components into an optimized system specifically developed for modern combat vehicle applications is then provided, including an example of how the process was employed to develop an advanced powertrain for a tactical vehicle demonstrator based on military optimized off-the-shelf components. The paper concludes with a summary of some further military specific engine and transmission technologies trends to be considered as part of an optimized mobility solution for heavy combat vehicles.