• The liquid thermal conductivities of D 5 and MD 2 M were measured. • A comparison was made between the experimental data and previously reported values. • The present experimental thermal conductivities were reproduced with a high-accuracy equation. In this work, the liquid thermal conductivities of Decamethylcyclopentasiloxane (D 5) and Decamethyltetrasiloxane (MD 2 M) were measured by using the transient hot wire method. The measurement was conducted in the temperature range of 253.15 K to 353.15 K and pressures ranging from 0.1 MPa to 8.0 MPa, with an uncertainty of 3.0 % in the present measurements. Besides, an empirical correlation was used to represent the experimental data. The Average Absolute Deviation (AAD) between the experimental data and calculations for D 5 and MD 2 M are 0.34 % and 0.31 %, respectively. This study provides accurate liquid thermal conductivities of D 5 and MD 2 M. The present experimental thermal conductivity data are useful for the design and optimization of the relevant heat exchange system. [ABSTRACT FROM AUTHOR]