Effect of X on the Transport Properties of Skutterudites LaFe 4X12 (X: P, As and Sb) Compounds. -The effect of substituting P by As and As by Sb on electronic transport properties in LaFe 4X12 (X: P, As, Sb) is investigated by calculating the electronic band structures with the all-electron full-potential linear augmented plane wave plus local orbitals method within the Becke-Johnson potential. Results show that the substitution has a significant influence on the bands dispersions, bond lengths, effective masses, the carriers mobility, and hence the transport properties. Replacing P by As increases the carriers concentration with temperature while replacing As by Sb does not show a significant increase. LaFe4Sb12 exhibits a low electronic thermal conductivity at 50-600 K with LaFe 4P12 showing the lowest at >650 K. Seebeck coefficients and power factors of all compounds increase with temperature and reach maximum values over the whole temperature range for LaFe 4Sb12. -(RESHAK, A. H.; J. Alloys Compd. 651 (2015) 176-183, http://dx.