Popularity of cloud computing have increased especially in the last five years among companies, but also, among individual users. This is due diversity of services provided by cloud, that are organized in software, platforms and infrastructures. Some of the major benefits in adopting cloud are cost reduction, availability of resources, flexibility. Even if it is powerful, cloud computing has some issues, one of them being security. Due to its complex architecture, cloud inherits all security issues of its components. A relatively new approach in cloud security is artificial neural networks, which is used especially in intrusion detection. In this paper we will present some security models based on ANNs applied in cloud computing and which are their results.