The weight, height, body mass index (BMI), waist/hip ratio, serum retinol and alpha-tocopherol and lipid profiles of 16 overweight (BMI > or = 25.0 kg/m2) Thai males and 56 overweight females, compared with 14 males and 58 females in a control group (BMI 18.5-24.9 kg/m2), were investigated. Subjects for the study were those persons who turned up regularly for physical check-up at the Outpatient Department, General Practice Section of Rajvithi Hospital, Bangkok. The study was conducted between December 2000-March 2001. Higher levels of cholesterol, LDL-C, LDL-C/HDL-C ratio were found in the overweight compared with the control subjects. Statistically significant higher triglyceride levels were found in the overweight compared with the control subjects. The median serum retinol concentration in overweight subjects was 2.80 mumol/L (range 0.53-4.62 mumol/L) compared with 2.97 mumol/L (range 1.21-4.12 mumol/L) in control subjects (p = 0.0736). The median serum alpha-tocopherol concentration in overweight subjects was 17.30 mumol/L (range 6.29-28.65 mumol/L) compared with 18.75 mumol/L (range 5.30-30.28 mumol/L) in control subjects (P < 0.05). The median values of retinol and alpha-tocopherol serum concentrations in the overweight and obese males were lower than those of the overweight and obese females. A total of 6.3% (1 out of 16) and 12.5% (2 out of 16) of the overweight/obese males had decreased retinol and alpha-tocopherol levels, while the overweight/obese females had decreased retinol and alpha-tocopherol level of 1.8% (1 out of 56) and 10.7% (6 out of 56), respectively. A total of 12.5% and 39.3% of the overweight/obese males and females had cholesterol concentrations of > or = 6.48 mmol/l. However, the prevalence of low HDL-C (HDL-C < or = 0.91 mmol/l) was found to be 50% in the overweight and obese males and 10.7% in the overweight and obese females. Statistically significant associations were found between age, cholesterol, LDL-C, and serum alpha-tocopherol in the overweight and obese male and female subjects. A negative correlation was found between weight, BMI, AC, MAMC, hip circumference and serum retinol in both the overweight and obese subjects. A negative correlation was found between weight, BMI, MAMC, waist, hip circumferences and serum alpha-tocopherol in both the overweight and obese subjects.