Today and even more tomorrow we will not have the capability to protect us against more than a few cruise missiles against a few assets. Recently analyses have focused on how to shoot down cruise missiles. Electronic warfare is another form of defence. A preliminary study is done on how to use electronic warfare against cruise missiles within the project Analyse of Threat Systems. This report is focusing on some ground elements for electronic warfare against cruise missiles and show some situations where electronic warfare could be useful. The study will continue with some deeper analyses. Electronic warfare against cruise missiles with military GPS and inertial navigation can be hard especially if considering deleterious effect against civil GPS, both domestic and international applications. Electronic warfare with noise jamming can be used against cruise missile systems of lesser technical level and against very slow flying cruise missiles. This means that electronic warfare could be used to reduce the demands on the combat systems. Intelligent jamming must be used against technical advanced cruise missile systems. For effective electronic warfare the missile navigation system must be known and the cruise missile must be detected and identified many minutes before entering the target area.