Highly b-axis oriented polycrystalline Ni-doped La5Ca9Cu24O41 thin films have been grown on (0 0 1) SrTiO3 substrates using the pulsed laser deposition technique. EDX measurements have revealed nearly stoichiometric target-to-film transfer of Ni concentration up to 6.6 at.%. The 3 omega method has been employed to carry out thermal conductivity measurements in the range 90-300 K. The results indicate that the out-of-plane thermal conductivity (kappa(b)) decreases with increasing Ni doping level. The temperature dependence of kappa(b) observed in pristine and Ni-doped films is similar to that observed in polycrystalline pellets indicating that the grain boundaries play a significant role in the heat transport. (C) 2010 Elsevier B. V. All rights reserved.