Protecting crop yield under drought stress is a major challenge for modern agriculture. One major biotechnological target for improving plant drought tolerance is the genetic manipulation of water stress response to the phytohormone ABA. Previous genetic studies indicated that constitutive down-regulation of Arabidopsis farnesyltransferase resulted in enhanced ABA sensing and stomatal closure. Here we present field results on the genetically engineered canola using a conditional and reversible down-regulation of farnesyltransferase approach. Field experiments were conducted under water-limited and well-watered conditions in Alberta, Canada from 2002 to 2004. Eight independent transgenic events, designated as YPT 1 to 8, and parent (DH12075) were included in 2002 and two most ABA sensitive events (YPT 1 and YPT 2) and parent were included in 2003 and 2004 for further defined field studies. Seedling vigor, plant stand establishment, days to flowering, plant height, lodging, days to maturity were measured, and seed yield was determined. In 2002, the yields of six transgenic YPT lines were higher than that of DH12075, whereas two other transgenic lines (YPT7 and 8) produced similar yield to the control. Transgenic YPT 1 produced 30% higher yield than DH12075 under drought condition. In 2003, there was no significant yield difference among tested lines under well-watered condition. Yields of transgenic events were significantly higher than those of parent under drought condition. In 2004, YPT1 and YPT2 produced 10 and 6% higher seed yield than DH12075 under water limited conditions and the difference was significant (p<0.05). In all three years, there were no significant differences among transgenic lines and DH12075 for seedling vigor, plant stand establishment, days to flowering, plant height, lodging and days to maturity. Using protein farnesyltransferase as an effective target, these results represent a successful demonstration of engineered drought tolerance and yield protection in a crop plant under field conditions.