[en] The magnetic properties of the RRh₄B₄ (R represents rare-earth metal) compounds are discussed in terms of a combined crystalline-electric-field and molecular-field approach. Magnetization data taken on single-crystal ErRh₄B₄ in five orientations are used to obtain the crystal-field and molecular-field coefficients, resulting in a complete analysis for the paramagnetic properties of this compound. The crystal-field parameters are additionally used to discuss all previously published magnetic data for polycrystalline RRh₄B₄ compounds. For these highly anisotropic materials, the effect of preferential crystallite orientation on the observed data is pointed out. Consideration of the variation of the magnetic transition temperature T/sub m/ between different constituent rare earths has verified a previous conclusion that the crystal field has a pronounced effect on T/sub m/, but this alone does not fully explain the observations