Recent studies have identified several factors which may affect human health and life expectancy in northern Finland. They have shown that antioxidants, infections, genetic or environmental factors may affect the development of and morbidity/mortality from cardiovascular diseases, cancer, diabetes mellitus and other diseases in the northern provinces of this country. Both the occurrence and mortality from coronary heart disease (CHD) is low in the northernmost part of the country, i.e. Mountain Lapland or the Saami area, compared with that in whole country or a neighbouring region to the south in central Lapland. The mortality from all diseases is also low in communities in Mountain Lapland, and high in central Lapland in communities such as Kittilä and Kolari. High scrum antioxidants, alpha-tocopherol (vitamin E), albumin and selenium levels have been measured in men living in the northernmost part of the country, where the death rate from CHD is low. Low serum alpha-tocopherol and albumin levels were typical of men living in rural communities with high CHD mortality, e.g. Kittilä community. Serum antioxidant levels were related to the diet; alpha-tocopherol increased with the consumption of reindeer meat and selenium with fish consumption. Our earlier studies have also identified a low Chlamydia pneumoniae IgA antibody titer in men living in Mountain Lapland compared with men in the neighboring region to the south in central Lapland with high CHD mortality. An elevated Chlamydia pneumoniae IgA antibody titer was associated with low serum alpha-tocopherol level. The people of Saami origin, an ethnic minority living in northernmost Finland, have a high apolipoprotein (apo) E e4 allele frequency and high serum cholesterol. They also have more apo A-IV-2 allele than most of the studied populations, and their HDL cholesterol levels are higher in apo A-IV-2/1 than in apo A-IV-1/1 phenotypes. Our earlier studies indicate that people living in northeastern Finland, west of smelters in Kola Peninsula may be exposed to heavy metals such as cadmium and mercury. Blood cadmium was related to blood pressure and high in men with arterial hypertensive disease. The investigations presented in this article form a good basis for further studies that clarify underlying reasons the health problems in the north.