We aimed to construct blood pressure (BP) references for the Polish preschool children and to compare them with the United States, German and European references. BP was measured oscillometrically using a validated device in 4378 randomly selected Polish children aged 3-6 years who were free of chronic diseases and behaved quietly during BP measurement. Height and weight were also measured. Gender-specific BP percentiles were constructed for age and height simultaneously with the use of quantile regression and a polynomial regression model. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure reference percentiles by gender, age and height are presented. The Polish preschool children's 90th and 95th SBP and DBP percentiles were mostly lower than those in the United States, German and IDEFICS study BP references. Compared with the German oscillometric BP reference and with the United States sphygmomanometric BP reference, differences in the 95th SBP percentiles ranged by age from -5 to 0 mm Hg and from -2 to -1 mm Hg, in boys and girls, respectively, whereas the differences in the 95th percentiles of DBP ranged from -7 to -1 mm Hg and from -5 to -1 mm Hg, in boys and girls, respectively. Polish preschool children's BP percentiles based on measurements with the use of a validated oscillometric device in a nationally representative sample are lower than those from the current United States, German and European references. When interpreting BP measurements in children, adequate referential values should be used.