The synthesis and biodistribution is described for a new 99mTc-labeled fatty acid. The requisite diaminodithiol (N2S2) ligand, 9,10-bis[N-(2'-methyl-2'-mercapto)propyl] aminooctadecanoic acid, was prepared in nine steps from ethyl oleate and characterized by fast atom bombardment mass spectrometry and elemental analysis of its nickell(II) complex. The radiolabeling procedure provided a liposoluble 99mTc-labeled complex (99mTc-11) which was administered intravenously to rats concomitantly with 15-(p-[125I]-iodophenyl) pentadecanoic acid (IPPA). The myocardial profile of 99mTc-11 was inferior to that of IPPA.