The complex equilibria between Ag(I) and thiourea or N-alkyl-substituted thioureas have been investigated in ethanol by potentiometry at different temperatures in the range 0-45 degrees C. The free energy, enthalpy and entropy changes at 25 degrees C and ionic strength mu=0 for the formation of mono-, bi- and tri-coordinate compounds are given. The investigated alcohols favour the complex formation, but specific factors operate on the transfer of each reaction from water to methanol to ethanol. Interaction between tetramethylthiourea and Ag(I) involves a different mechanism compared with the other thioureas owing to the different electronic structure of the ligand. The ranked affinity sequences of the ligands follow different orders according to the coordination level of the substratum.