Am(III) is one of the most hazardous radionuclide present in nuclear fuel cycle. A new conformation ally constrained diamide, (N,N,N,N'-tetra-2-ethylhexy1)7-oxabicyclo[2.2.1]heptane-2,3-dicarboxamide (OBDA) was studied for Am(III) transport from HNO3 medium across a Supported Liquid Membrane. Transport rate was observed to be significantly fast with similar to 95% transport of Am(III) within 1 h using 0.1 M OBDA in the presence of 15% isodecyl alcohol (IDA)/n-dodecane as carrier. The mechanism of transport was investigated by studying various parameters like feed HNO3/NaNO3 concentration, OBDA concentration in the membrane, membrane pore size, membrane thickness etc. From these studies, the mechanism of transport was found to be diffusion controlled with diffusion co-efficient value of 5.1 x 10(-6) cm(2)/s. The membrane was found to be highly selective for tri- and tetra-valent actinides, and trivalent lanthanides. OBDA based membrane was found to be stable for at least for ten consecutive cycles of operation. (C) 2015 Elsevier B.V. All rights reserved.