Objectives: To provide current reference values for serum lipid and lipoprotein levels in Spanish adolescents according to age and sex. Methods: A cross sectional study conducted in five representative Spanish cities (Granada, Madrid, Murcia, Santander and Zaragoza) including a representative sample of 581 adolescents (299 male and 282 female), aged 13 to 18.5 years. Age- and sex-specific means, standard deviations and percentiles were determined for: Total (TC), high density lipoprotein (HDLc) and low density lipoprotein (LDLc) cholesterol, triglycerides, apolipoprotein A-1 and B-100, and lipoprotein(a). Results: The 90(th) percentile for TC was 4.95 mmol/L for males and 5.19 mmol/L for females. HDLc levels were significantly higher in females of all age groups. LDLc levels ranged from 2.32 to 2.54 mmol/L in males and from 2.38 to 2.62 mmol/L in females, peaking at 13 years of age in both sexes. Triglyceride levels tended to increase gradually and to peak at 17 years of age for both sexes. Apolipoprotein A-1 and B-100 levels paralleled those of HDLc and LDLc values, respectively. The geometric mean for lipoprotein(a) levels ranged from 0.44 to 0.57 mu mol/L in males and from 0.50 to 0.67 mu mol/L in females. Conclusions: The present study provides reference data on the distribution of lipid and lipoprotein levels of Spanish adolescents.