Extraction of La(III), Eu(III), Lu(III) and Am(III) from 1M NH 4SCN at pH ∼ 2·8 by tri- n-octyl-phosphine oxide (TOPO), tri- n-butyl phosphine oxide (TBPO), and tri- n-butyl phosphate (TBP) in xylene medium has been studied. In this connection extraction of thiocyanic acid from 1M NH 4SCN in the pH range of ∼ 2 to ∼ 3 by the three extractants in xylene has also been investigated. It has been found that thiocyanic acid is extracted as HSCN . R 3PO by the three extractants and equilibrium constants for this extraction have been calculated. The metal ions are extracted as neutral, solvated, probably anhydrous species M(SCN) 3. XR 3PO, X in general having the values of 4 and 3 for the lighter and the heavier lanthanides respectively. The complexes Nd(SCN) 3. 4TOPO and Er(SCN) 3. 3TOPO have been prepared and their absorption spectra has been recorded.