Aloysia triphylla (L'Her.) Britton (Verbenaceae) is a deciduous shrub known as lemon verbena and is an important medicinal and aromatic plant.  The experiments were carried out at the Farm of the Medicinal and Aromatic Plants, and  Laboratory of Agric. Botany Dept., Fac. Agric., Mansoura Univ. during the seasons of 2006, 2007 and 2008.  The experiments aimed to studythe effect of wounding and auxin type and concentration on rooting of Aloysia triphylla plant.  Anatomical changes during the formation and emergence of adventitious roots were performed in addition to determination of endogenous IAA.  The results showed that both IBA and NAA increased rooting percentage and number and length of roots of the cutting.  The effects of both growth regulators depended on the concentration used. Best results for number and length of roots per cutting were achieved using 2000 ppm IBA and 1000 ppm NAA. Wounding of the cuttings in addition to the use of auxins improved rooting of the cuttings, and the best rooting resulted from wounding the cutting plus treating them with 2000 ppm IBA and 1000 ppm NAA.  Anatomical studies showed that narrow phloem tissue, cambial zone and vascular rays beside badly and slowly formation of the vascular connection between the new roots and the vascular tissues of the cuttings seemed to be mostly responsible for difficult to root cuttings. Results showed also that number of roots per cutting, and root length were increased with increasing endogenous IAA content. This increase correlated with auxin treatments, auxin type and their concentrations.