Interhospital transfer of critically ill patients is associated with hemodynamic and pulmonary deterioration. In order to minimize additional risks of transport, a mobile intensive care unit with a specialized retrieval team (MICU) service was established at our tertiary referral center in 2009. In order to see the effects of this new transporting mode, we performed a prospective audit to investigate the quality of interhospital transfers to our university affiliated ICU. We evaluated transfers performed by MICU from March 2009 until December 2009. Data on fourteen vital variables were collected at the moment of departure, arrival and 24h after admission. Variables before and after transfer were compared using the Paired-Sample Test. Major deterioration was expressed as a variable beyond a predefined critical threshold. Results were compared to the data of our previous study concerning interhospital transfer performed by ambulance (1). 74 transfers over a 10-month period were evaluated: 84 percent of all patients were mechanically ventilated and 53 percent were on vasoactive agents. At arrival, systolic blood pressure, glucose and haemoglobin were significantly different compared to departure, although major deterioration never achieved significant values. 38 percent showed an increase of total number of variables beyond threshold at arrival, 32 percent exhibited a decrease of one or more variables beyond threshold and thirty percent had an even number. There was no correlation with the duration of transfer or severity of disease with patient status at arrival. ICU mortality was 28%. Compared to the transfers performed in 2005, there were far less incidents in the current situation: 12.5% vs. 34%. In the current study, all incidents were due to technical problems. Although mean APACHE II score was significantly higher, patients transferred by MICU showed less deterioration in pulmonary parameters compared to the patients transferred by ambulance. Conclusion Transfer by MICU appears to be well prepared and imposes minimal risk to the critically ill patient when compared to transfer performed by ambulance. The implementation of a transport protocol with a mobile Intensive Care Unit and a specialized retrieval team has therefore led to an improvement in quality of (critical) care.