Lentil cotyledonary nodes are some of the most regenerative tissues in legumes. Attempts to transform them by vacuum filtration have been Limitedly successful. This report describes a rapid and convenient transient expression protocol based on vacuum infiltration of Agrobacterium cells into lentil cotyledonary nodes. Vacuum-infiltrated tissues had significantly (P < .05) higher transient GUS expression than did noninfiltrated tissues. Under optimal conditions (infiltration at 200 mmHg for 20 min), 95% of the Agrobacterium-infiltrated explants exhibited an average of 16 blue foci. We believe this to be the first report of this technique for transient gene expression in lentil cotyledonary nodes.