Due to its geographic position, geomorphology and certain signs of frequent occurrencesof atypical conditions, the south area of the southern part of the Kornati islands and the island of Žirje is very interesting for the thermohaline analysis. The analysis has not been completed,however, the activities necessary for getting an insight into justifiability and the need for radical interventions have been made. On the basis of the data obtained from longtime measurements, separate analyses of the sea water temperature, salinity and density have been made, defining annual courses of mean monthly and extreme values, mean monthly values at characteristic depths, and vertical distribution of mean monthly values. Special importance was given to external and internal influences.