OBJECTIVE: In our area patients seen by the Prehospital Emergency Physician (PEP) are all classified according to the Severity of Injury/Illness Index (SIII) groups 0 to 7. This classification enables the evaluation of the optimal use of the PEP and focus on education. The PEP should only be dispatched to the SIII groups 4-7 (severe illness/injury). Choosing six main groups of diagnoses we describe the individual distribution of SIII to reveal their severity. METHODS: The local Emergency Medical Service (EMS) system in Aalborg, a small-sized urban city with approximately 200.000 inhabitants, dispatches a PEP for major injury and severe medical conditions. For 72 months we extracted data regarding six main groups of diagnosis according to the ICD-10-system: Metabolic diseases, Diseases of the Central Nervous System (CNS), Diseases of the circulatory system, Diseases of the respiratory system, Trauma and Poisoning. RESULTS: 8249 patients were included in the six main groups. 6061 patients (73,5%) were classified in groups 0-3. 2188 patients (26,5%) were classified in groups 4-7. Poisoning, diseases of the respiratory system and diseases of the circulatory system shows a more severe pattern, contrary to diseases of the CNS, metabolic diseases and trauma. All the diagnostic groups peek between SIII groups 2 and 4. CONCLUSION: Uncovering the distribution of SIII according to these six diagnostic groups enable us to consider a more specific dispatch manual and even more focused education of the EMS personal. A more detailed study of the exact diagnosis in each group is necessary.