A conformationally constrained diamide, (N,N,N´,N´-tetra-2-ethylhexyl) 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxamide (OBDA) was found to transport Am(III) from HNO₃  medium across a Supported  Liquid Membrane  with  good  transport  rate, diffusion coefficient and selectivity over fission products. 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-ethylhexyl)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 ∼95% transport of Am(III) within 1 h using 0.1 MOBDA 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 × 10⁻⁶cm²/s. The membrane was found to be highly selective for tri- and tetravalent actinides, and trivalent lanthanides. OBDA based membrane was found to be stable for at least for ten consecutive cycles of operation.