Each day two criminal phenomena dominate the news. These criminal phenomena are terrorism and organised crime. This study tries to compare terrorism and organised crime when it comes to the phenomena, including organisation and financing of the organisation. Furthermore, this article seeks to examine whether terrorist groups and organised crime groups cooperate. This study shows that since the nineties terrorism and organised crime have much in common. Both in terms of organisation and funding the two criminal phenomena often use the same methods. However, every organisation is unique. In addition, it also appears that terrorist groups regularly cooperate with organised crime. This mainly out of necessity.