Friendly or green compositions are being sought in many kinds of applications, such as fertilization, building materials, energy generation, and so on. Thus, this classification (green) can be established after the subjection of the compound to a thorough toxicity study. The research for low toxicity and no damage to the environment has stimulated the development of specific investigation lines in many areas. Inevitably, the criteria for safe handling, sensitivity and, mainly, specific impulse (efficiencies) of propellant compositions is still superior compared to ecological appeals. Nowadays, however, the solid or liquid propulsion, as aerospace as military, has already compounds to efficiency and eco-friendly characteristics. Thus, the chapter proposed will show a review in the energetic materials area, aiming at the most promising materials to be used as oxidizers and combustibles in a green propulsion system.