Triglycerides/HDL-cholesterol ratio (TG/HDL) is an easy resource determination and it has good correlation with the HOMA index in adults. Due to physiological insulin resistance (IR) in adolescence it is necessary to find markers of IR independent of age, sex and pubertal stage. The objective was to identify reference values of TG/HDL ratio in a population of adolescents without cardiovascular risk factors. We evaluated 943 adolescents, 429 females and 514 males between 11 and 14. Anthropometric measures were determined and body mass index was calculated (BMI). Blood was extracted after 12 hours of fasting to determine glucose, triglycerides, HDL. The metabolic syndrome (MS) was diagnosed according to criteria of NCEP/ATP III modified by Cook. We excluded adolescents with MS or any component of it. We evaluated 562 adolescents (289 women and 273 men) with a weight of 48.91 +/- 6.51kg, BMI: 18.95 +/- 1.78, systolic blood pressure of 108.12 +/- 13.60 mmHg, diastolic blood pressure: 63.82 +/- 9.43 and waist circumference: 65.09 +/- 4.54 cm. TG/HDL ratio was 1.25 +/- 0.43, with a 95 percentile of 2.05. In adults, TG/HDL ratio greater than 3 is a marker of insulin resistance. We believe that a higher value to 2.05 might be a good index of insulin resistance in adolescence. TG/HDL ratio has the advantage of being methodologically simpler, more economical and independent of pubertal stage.