Density measurements are reported performed on three 1-alkyl-3-methylimidazolium-based ([C-n-mim], n = 2, 4, 6) ionic liquids with tetrafluoroborate anion at atmospheric pressure at 15 temperatures from 281 to 353 K. The buoyancy rnethod was employed, using the microbalance of the Kruss K100MK2 tensiometer. At each temperature from 33 to 55 individual buoyancy readings were taken in most cases. The density average values at particular temperatures are presented with estimated total standard uncertainty less than +/- 0.4 kg m(-3) (3.3 x 10(-4) rho). An empirical density-temperature equations have been developed describing the temperature dependence of each ionic liquid density. The 58 new experimental data points on the density-temperature relation of the three ionic liquids of interest are means calculated from about 3000 individual density readings, which have been altogether taken in the present study. (C) 2009 Elsevier B.V. All rights reserved.