Sodium azide (NaN3) still remains a popular plant mutagen. In the present investigation, its effects on the cytogenetic changes were studied in root tip cells of Trigonella foenum-graecum, which is an economically and medicinally important crop of India. Trigonella seeds were germinated after treating with various concentrations of sodium azide (0.1, 0.2, 0.3, 0.4 and 0.5%) at 24 +/- 1 degrees C for 72 It and the cytogenetic changes evaluated. The study revealed that sodium azide decreased the percentage seed germination, radicle length (at higher dose), mitotic index, and caused an increase in the chromosomal aberrations in a dose-dependent manner. Altogether, the root tip cells of the sodium azide-treated Trigonella seeds exhibited an increased incidence of chromosome stickiness, bridge formation, precocious separation and lagging chromosomes. (c) 2007 SAAB. Published by Elsevier B.V. All rights reserved.