Picloram (4-amino-3,5,6-trichloro-2-pyridine-carboxylic acid) is a very similar to auxin type plant growth regulators and also a synthetic systemic herbicide. The genotoxic effects induced by picloram in root meristems of Allium cepa in tissue culture condition were studied. Mitotic index, mitotic phases and mitotic abnormalities analysed after Allium bulbs exposure to six different concentrations (0.67, 1.34, 2.01, 2.68, 3.35 and 4.02 mg/L) of picloram at 24 and 48 h in agar solidified Murashige and Skoog medium. The mitotic index was decreased significantly when compared to controls at both 24 and 48 h treatments using the highest four concentrations of picloram (2.01, 2.68, 3.35, 4.02 mg/L). However, mitotic index at 0.67 and 1.34 mg/L concentrations of picloram were relatively similar level of control groups. This chemical induced a statistically significant difference in the percentage of prophase and telophase cells at 4.02 and 3.35 mg/L concentrations respectively, at 24 h treatment. Picloram did not statistically significant increased mitotic abnormalities when compared to controls at both treatment periods. These results showed that picloram do not have genotoxic potential at low concentration in cultured A. cepa root tips.