Greenhouse and laboratory studies were conducted to examine the effects of site of plant exposure to glyphosate spray on efficacy, absorption, and translocation in pitted morningglory. Absorption of 14C-glyphosate in four-leaf pitted morningglory gradually increased with time from 19% at 1 h after treatment (HAT) to 44% at 192 HAT. The amount of 14C translocated with time ranged from 0.4% at 1 HAT to 25% at 192 HAT. Vining 1-m tall plants were controlled 75 to 100% when the top-, middle-, bottom one-third, or entire plant was treated with 1.38 or 2.76 kg ha−1 glyphosate, with control affected more by glyphosate rate than plant section exposed to glyphosate spray. Absorption of 14C-glyphosate at 96 HAT was similar whether it was applied to the top-, middle-, bottom one-third, or entire plant of 1-m tall pitted morningglory. The amount of 14C translocated out of the treated area (5 to 6%) did not differ whether it was applied to top-, middle-, or bottom one-third plant section. Results indicate that absorption and translocation of 14C-glyphosate in pitted morningglory was rapid and increased with time. Treating any one-third section of pitted morningglory plants was as effective as entire plant exposure, and control with glyphosate is more affected by rate than the degree of plant exposure to glyphosate.