The uptake and transport of carboxyl-labeled and unlabeled butoxyethyl esters and ammonium salts of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) by honey mesquite (Prosopis juliflora (Swartz) DC, var. glandulosa (Torr.) Cockerell) leaves were compared as measured by liquid scintillation counting and gas chromatography. Absorption of 2,4,5-T was determined by assaying leaf-rinsing solutions and extracts of treated leaves. Transport of 2,4,5-T was measured by determining amounts of 2,4,5-T found in stem tissue. The methods of analysis gave comparable results when extraction, cleanup, and analytical procedures were identical. When cleanup and methylation procedures were eliminated for the radioisotopic analyses, radioisotopic analyses gave significantly higher values for extracts of treated leaves than did gas chromatographic analyses. Larger amounts of 2,4,5-T were recovered from leaves treated with the butoxyethyl esters of 2,4,5-T than with ammonium salts.