The influence of the severe climate and geographical conditions at the Svalbard archipelago (78-79 degrees N) on serum lipid levels were measured in Caucasian miners who had arrived from the southern part of Ukraine and Russia (48 degrees N). The persons included in the study were randomly divided in five groups according to their time of living (1, 3, 6, 12 and 24 months) at Svalbard. Blood sampling took place during a two week period in January, when the Svalbard archipelago is into its polar night. General elevated levels of triglycerides were found in group I-III (1, 3 and 6 months stay), whereas the values measured in group IV and V (12 and 24 months stay) were somewhat lower. This apparent decline in triglycerides was paralelled by generally elevated levels of HDL cholesterol. The serum level of phospholipids was similar in all groups. All the level of free fatty acids was apparently higher in groups IV and V, particularly 18:3 and 16:1. These results may be indicative of a rise in triglyceride consumption after about a 12 month stay in the archipelago. Besides, the elevated levels of 18:3 and 16:1 fatty acids imply dietary modifications of the serum fatty acids.