Background/aim: The high prevalence of non-communicable diseases and their risk factors among the general urban population of Tehran necessitates an urgent implementation of nutritional interventional programs to curtail these risk factors. This study aimed to provide preliminary data on the knowledge, attitude and practices of urban Tehranian adults regarding nutrition and their relation to major non-communicable disease risk factors and to assess the need for educational interventions., Methods: This cross-sectional study was performed within the framework of the second phase of the Tehran Lipid and Glucose Study (TLGS). Subjects were 826 individuals, 369 men and 457 women, aged 20-70 years old, selected randomly from among 15,005 participants in the TLGS. Knowledge, attitude and practices of subjects were assessed by a 'knowledge, attitude and practice' questionnaire; height, weight, waist and hip circumferences were measured, and BMI and waist to hip ratio were calculated. Biochemical data including fasting blood glucose, cholesterol, triglycerides and HDL-cholesterol were measured, based on standard protocols, and LDL-cholesterol was calculated. Associations between nutritional knowledge, attitude, practice, sex, age and educational level, and between knowledge, attitude and practice and BMI, waist to hip ratio and levels of lipid and lipoproteins, were determined., Results: For knowledge 26.5, 52.7 and 20.8%, for attitude, 27.6, 48.9 and 23.5% and for practice, 27.4, 51.7 and 20.9% of individuals had desirable, moderate and weak knowledge scores, respectively. With increases in educational levels, knowledge scores increased (p < 0.001). Attitudes of illiterate and poorly literate groups were weaker than those of other groups (p < 0.001). However, illiterate and poorly literate groups had higher practice scores as compared to middle school and high school graduates (p < 0.001). Mean practice scores of university graduates were higher than high school graduates (p < 0.05). Those aged 30-50 years had higher knowledge scores than older individuals (p < 0.001). LDL- and total cholesterol were correlated to practice scores (p < 0.001, r = 0.23). Subjects with borderline triglyceride levels had better practice scores than normal individuals (p < 0.001)., Conclusions: The findings revealed that age, educational level and gender are factors that can influence knowledge, attitude and practices, regarding nutrition. It is vital to develop approaches and implement programs to improve the nutritional practices of the population., ((c) 2010 S. Karger AG, Basel.)