Potential long-term negative effects of increased vitamin D consumption are not thoroughly examined. The aim of this study was to investigate possible negative effects of vitamin D supplementation on serum lipids and lipoproteins. A 1-year long randomised double-blinded placebo-controlled intervention study with two doses of vitamin D3 (10 and 20 microg/day) was carried out among 89 women (18-53 years of age) and 84 men (18-64 years of age) of Pakistani origin living in Denmark with low vitamin D status. This study did not find changes in total cholesterol, LDL-cholesterol, HDL-cholesterol, LDL-cholesterol/HDL-cholesterol ratio, VLDL-cholesterol and triacylglycerol after daily supplementation with 10 or 20 microg vitamin D for 1 year. In conclusion, increasing the vitamin D intake by 10-20 microg per day for 1 year is safe for Pakistani immigrants with regards to serum lipids and lipoproteins.