Mortality in the Balearic Islands, when considered in terms of collective health, is high, compared to other autonomous communities in Spain. This is a surprising situation due to the apparently high degree of development in the Balearics. But probably the concept of development has to be revised. From this fact, a study about the causes and determining factors for such a high mortality rate is carried out. This is done taking the autonomous community as the territorial unit, whereas the chosen period is 1990-94.

· The general concept of mortality, in connection with collective health, and its indicators are analysed. Good indicators in this sense are the standardised rate of mortality, life expectancy at birth and the risk or specific mortality rates by age (profiles of mortality).

· The Balearic Islands exhibit the fifth highest standardised rate in Spain (among 17 autonomous communities), the lowest life expectancy at birth and the highest risk of mortality at some ages (20 to 25 and 40 to 45).

· 23 socioeconomic indicators have been selected as determining factors of mortality.

· The main component analysis has been used to reduce the 23 socioeconomic indicators into five large "factors", the three most important being people's educational level, their nourishing regime and their demo-economical level.

· By using the cluster analysis (similarity), the 17 autonomous communities have been grouped into larger territories regarding (a) the socioeconomic factors, (b) the profiles of mortality.

· Classical two-dimensional and multidimensional statistical analysis, as well as a combined cartography developed "ad hoc", have been used.

· The most remarkable results are: (a) the direct causes of the apparently paradoxical present situation in the Balearics are a much higher incidence of heart diseases than the Spanish average for ages between 15 and 64, and also a higher incidence of AIDS at young ages (15 to 44), (b) societal determinants that are explanatory enough (in the statistical sense) of the above mentioned facts are a relatively low educational level, associated with a relatively poor density of medical professionals, and the high economic and demographic dynamism, which is connected to a high immigration and social destabilisation.