There are 20 SOS Alarm emergency dispatch centres in Sweden, and from these centres approximately one million ambulances are dispatched each year. The aim of the study was to explore factors and circumstances that contributed to misjudgements or filed complaints in emergency medical dispatching filed at the Patient Advisory Committees (n=24), the Swedish National Board of Health and Welfare (n=20) and the Medical Responsibility Board (n=10). This is a retrospective study of all decisions on complaints made between 1991 and 2000, and the data were analysed in two phases. In the first phase, categories of cause were revealed, and in the second phase, factors and circumstances were identified that related to misjudgements or filed complaints. The findings show that in nearly half (23/54) of the complaints, the assessments were stated as been made on the basis of second-hand consultations, e.g. the SOS operators had not spoken directly to the ill person. In 19 out of 21 complaints dealing with the decision-making process, the assessments were made on second-hand information. Second-hand information may constitute an aggravating circumstance in assessing the urgency of the care needed on the telephone. The findings suggest that the call receivers should be more cautious when undertaking assessments on the basis of information provided by a third person.