Worldwide, there is a high risk of medical complications or death in police custody. This risk is often increased by unclear legislation, a lack of clearly defined responsibility and medical examination standards. Any solution to these problems requires as a very basis the systematic analysis of the medical examinations that determine whether a person is fit to be detained in custody. We analysed a total of 3,674 medical records on fitness for custody, taken from two large German towns (Halle/S and Bremen). The examined individuals were predominantly males or of a younger age. The indication in the majority of cases was acute alcoholic intoxication or drug withdrawal syndromes. Traumata and internal or mental diseases were also quite frequent. For approximately 50% of all cases, fitness for custody was declared on certain conditions. Only 39.8% were found to be unconditionally fit for detention in custody. In just under 10% of the cases, the person was found unfit for custody. These cases concerned mainly persons with psychological symptoms and advanced alcohol or drug withdrawal syndromes. We were able to show that the recent introduction of new police custody regulations in Halle/S had a significant influence on the medical decision on fitness for custody. Our detailed assessment has provided us with the basis to develop solutions for the improvement of medical care in police custody. The focus lies here on the organisation and legal regulation of the medical aspects of custody but also on policing and medical work.