The influence of hyperglycaemia on the FDG uptake of regular adipose tissue at PET examinations was studied in clinical patients. Methods: The report constitutes a sub-study of 500 consecutive clinical examinations evaluated in retrospect. The inclusion criteria comprised examinations with a normal, or a near normal FDG distribution. Patients who had been subjected to chemotherapy or radiotherapy <4 weeks prior to the examination were excluded. Otherwise, inclusion was made irrespective of concurrent diseases and/or therapy. In the current study, a sub-group of 62 patients with increased blood glucose levels (≥ 7.0 mmole/l) was compared with another 62 patients being paired with regard to age and gender and showing blood glucose levels within normal range (≤ 6.0 mmole/l).