Moisture-dependent physical properties of the seed of ajwain (Trachyspermum ammi L. syn. Carum copticum Benth. & Hook. f.) were studied at moisture contents of 4.39, 10.42, 15.36 and 21.6% (w.b.). The length, width, thickness, geometric mean diameter, angle of repose and thousand-seed mass increased significantly (p < 0.05) from 1.91 to 2.20 mm, 1.15 to 1.22 mm, 0.87 to 0.93 mm, 1.24 to 1.35 mm, 30.27 to 36.65 degrees and 0.89 to 1.19 g, respectively, with increase in moisture content from 4.39 to 21.6% The sphericity, true density and porosity decreased significantly (p < 0.05) from 0.65 to 0.61, 941.02 to 780.59 kg m(-3) and 58.04 to 50.99%, respectively, with increase in the same moisture content range. However, the decrease in bulk density was not significant (p > 0.05). The static coefficient of friction (mu) increased significantly from 0.509 to 0.571 and from 0.488 to 0.532 for plywood and mild steel, respectively, with increase in moisture content from 4.39 to 21.6 %.