The Sami people are the Natives of northern Scandinavia. The knowledge of the health and living conditions of the Swedish Sami is extremely limited which is in contrast to the large amount of detailed information on health and socioeconomic issues that is available for other circumpolar Natives. The encounter with the western society and the acculturation process has for many native populations had serious health consequences, causing a dramatic increase of lifestyle related diseases such as cancer, diabetes, stroke, obesity and hypertension as well as a dramatic increase of suicide and drug abuse. The overall objective of this thesis was to investigate the health conditions of the Sami population of Sweden using causes of death and incidences of cancer and cardiovascular diseases (CVD) as health indicators, and to evaluate their possible association with acculturative factors such as assimilation, integration, separation and marginalization. A Sami population was identified containing a total of 41 721 individuals. Specific cohorts were selected from this population for the different studies. A four times as large demographically matched non-Sami control population was used for comparisons. A study of causes of death, 1961-2000, showed small differences in overall mortality and life expectancy between the Sami and the non-Sami. However, Sami men showed significantly lower mortality risks for cancers but higher for external cause of injury and Sami women higher risks for diseases of the circulatory system (CVD) and of the respiratory system. An increased risk of dying from subarachnoid haemorrhage (SAH) was observed among both Sami men and women. The increased risk of dying from accidents among male reindeer herders is suggested to be caused by the increased socioeconomic pressure and the extensive use of terrain vehicles. It is concluded that commercial reindeer management is one of the most dangerous occupations in Sweden. In a study of the cancer risk among the reindeer herding Sami between 1961-1997, an overall lower risk to develop cancers, particularly prostate and malignant lymphoma was observed among the reindeer herding Sami. The risk for stomach cancer was significantly higher in relation to their non-Sami neighbours. The Sami and the non-Sami had similar risk factor-patterns for CVD. The main differences were related to working conditions and lifestyle factors of the reindeer herding Sami - the women showed a more unfavourable risk factor pattern than the men. Higher incidences of stroke were observed among Sami men and women compared to their non-Sami neighbours while the mortality rates of stroke were similar. The mortality ratio of AMI was increased for Sami women in spite of similar incidence ratios. A higher risk of SAH was observed among all groups of Sami. According to traditional socioeconomic risk factors, the differences in the levels of income and education observed between the Sami and the non-Sami, were poorely associated with the disparities of CVD. As has been shown, only minor differences in the health indicators were found between the Sami and their non-Sami neighbours. This is in clear contrast to several other native populations for which the health situation is largely unfavourable in comparison with that of the general population. The observed differences between the Sami and the non-Sami probably reflect differences in lifestyle, psychosocial and genetic factors. The relation between these factors and the acculturation process is dicussed, and it is suggested that separation or segregation of the reindeer herding Sami and the assimilation of the other Sami have influenced the health condition of the Sami, but with the largest impact probably prior to 1961 and the earliest start of follow-up for the studies in this thesis. Thus, the similarities in health between the Sami and the non-Sami 1961-2002, are probably a result of centuries of close interaction that has caused similarities in culture, attitudes and lifestyle, as well as equal accessibility to the health care services and the social security systems.