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The crystal structure and magnetic properties of (NdxR1-x)(3)Fe24Cr5 (R = Gd and Tb) compounds with x = 0.0-0.8 have been investigated by means of X-ray diffraction and magnetic measurements. All the samples are single phase and crystallize in the Nd-3(Fe,Ti)(29)-type structure with space group A2/m. As the Nd content increases, the lattice parameters a, b, c and the unit-cell volume V increase in both the (NdxGd1-x)(3)Fe24Cr5 and the (NdxTb1-x)(3)Fe24Cr5 compounds due to the lanthanide contraction. The room-temperature easy magnetization direction changes to the [0 4 0] direction with increasing Nd content. The Curie temperature of (NdxGd1-x)(3)Fe24Cr5 decreases monotonically upon substitution of Nd for Gd, while the Curie temperature of the (NdxTb1-x)(3)Fe24Cr5 compounds decreases with the Nd content for x = 0-0.4 and increases for x = 0.4-0.8. The saturation magnetization M-S increases monotonically with increasing Nd content for both compound systems and can be described in terms of a simple dilution model. (c) 2005 Elsevier B.V. All rights reserved.