Prof. dr. Oerlemans focusses in his research on the relationship between the digitalisation of intelligence and the law. For example, the relationship between cyber security and national security, the regulation of signals intelligence, and the regulation of data analysis techniques. He also publishes about the intersection of intelligence and criminal law. 

His research is on the intersection of criminal law, administrative law, IT law, and privacy law. He regularly publishes blogs on his website jjoerlemans.com.