The Abdus Salam International Centre for Theoretical Physics (ICTP, Trieste, Italy) in cooperation with the International Atomic Energy Agency (IAEA, Vienna, Austria) is organizing a Workshop on "Nuclear Structure and Decay Data: Theory and Evaluation" to be held at ICTP in Trieste from 24 - 28 March 2014. The Workshop constitutes a unique opportunity for scientists to gain extensive and up- to-date training on the evaluation of nuclear structure and decay data, as developed to produce the Evaluated Nuclear Structure Data File (ENSDF) and Nuclear Data Sheets for use and adoption by the nuclear physics community. Reliable evaluated nuclear structure and decay data are of vital importance in a large number of energy and non- energy based applications such as power generation, materials analysis, dosimetry and medical diagnostics, as well as basic nuclear physics and astrophysics. Important features of these needs are satisfied by the work undertaken by the International Network of Nuclear Structure and Decay Data (NSDD) Evaluators. The main products of this worldwide network are the recommended data files and evaluated decay data.