Background: In patients with metabolic and nutritional disorders such as diabetes and hyperlipidaemia, where strict compliance to advice on timing and composition of food intake is important, the prolonged daylight fasting during the month of Ramadan could produce undesirable biochemical consequences. Aim: The study aimed to compare pre-and post-Ramadan lipid and lipoprotein pro®les in stable Kuwaiti hyperlipidaemic subjects attending a Lipid Clinic. Subjects and methods: The study population comprised 64 adult Kuwaitis (33 M, 31 F) who had been attending a Lipid Clinic for at least 12 months and were considered stable, without any acute systemic illness. At each clinic visit, the following parameters were measured: weight, total cholesterol (TC), triglycerides (TG), HDL, LDL, apo A-1, apo B, glucose and uric acid. These biochemical parameters were measured by routine automated analyzer techniques. The pre-Ramadan values comprised the means of two measurements taken at about 3 month and 1 month before commencement of Ramadan. Post-Ramadan values were obtained within 1 month of the end of the Ramadan fast. The parameters so obtained were compared in the whole group, and then according to gender, glycaemic status and modality of treatment (diet alone or with a ®brate or statin). Results and discussion: In the nondiabetic subjects, apo A-1 and apo A-1aapo B and apo A-1aHDL ratios were increased post-Ramadan (P`0.001). Weight did not change and the other lipid parameters Ð TC, TG, LDL, apo B Ð did not worsen. These observations, more consistent in the men than in the women, and in subjects treated with a ®brate or a statin rather than on diet alone, indicate a favorable coronary heart disease (CHD) risk pro®le. In the diabetic patients, these changes in the apo A-1 level and its ratio to HDL and apo B were also present, but TC and apo B levels increased, the latter signi®cantly (P`0.05). These divergent effects in diabetic patients could variably in¯uence CHD risk liability. Serum uric acid levels were also simultaneously reduced postRamadan in the non-diabetic subjects and those on statin treatment. Conclusion: When pre-and post-Ramadan lipid and lipoprotein pro®les were compared in stable hyperlipidaemic subjects attending a Lipid Clinic in Kuwait, the most consistent changes post-Ramadan were increased levels of apo A-1 and apo A-1aapo B and apo A-1aHDL ratios and reduced uric acid levels. Body weight remained essentially unchanged and the other lipoprotein and lipid parameters were not worsened. These results suggest that Ramadan fasting in hyperlipidaemic subjects might favorably in¯uence CHD risk.