The pure rotational spectrum of AlCCH in its ground electronic state ((X) over tilde (1)Sigma(+)) has been measured using Fourier transform microwave (FTMW) and mm/sub-mm direct absorption spectroscopy. AlCCH was created in a DC discharge from HCCH and aluminum vapor, either produced by a Broida-type oven, or generated from Al(CH3)(3) in a supersonic jet source. Rotational transitions were measured for five isotopologues of AlCCH, with C-13 and deuterium substitutions. From these data, rotational and Al and D quadrupole parameters were determined, as well as an accurate structure. AlCCH appears to exhibit an acetylenic arrangement with significant covalent character in the Al-C single bond. (C) 2012 Elsevier B.V. All rights reserved.