The gadolinium(III) beta-diketonate complexes and their adducts with neutral ligands such as triphenylphosphine oxide (TPPO), trioctylphosphine oxide (TOPO), hexamethylphosphoramide (HMPA), and dimethyl sulfoxide (DMSO) have been synthesized and examined as paramagnetic relaxation reagents in analysis of water-in-oil emulsions by the nuclear magnetic relaxation method. For all compounds the solubility in water and n-hexane has been determined. The dipivaloylmethanate complex Gd(DPM)3.TOPO (I) was found to show the best solubility in n-hexane (0.05 mol/l) as well as practical insolubility in water. When added to a sample of hydrocarbons (n-hexane, benzene, kerosene, oil), (I) caused a general enhancement of spin-lattice relaxation rates of both aromatic and aliphatic protons. In the study of kerosene-water and oil-water emulsions, the addition of 0.05% (I) was associated with shorter organic proton relaxation times than those of water protons and hence the relaxation curves might be successfully resolved into two components. The results presented demonstrate that (I) can be used as a paramagnetic relaxation reagent to determine components in water-in-oil emulsions.