AbstractThe extraction and determination by gas chromatography of 2,4‐dichloro‐ (2,4‐D) and 2,4,5‐trichloro‐phenoxyacetic acids (2,4,5‐T) as their methyl esters when present together in lawn fertilisers is described. The recovery of these herbicides varies with the composition of the fertiliser and four formulations have been studied to cover the most likely variations to be met in practice. The presence of dissolved hide meal results in extremely low recoveries. With this exception, recovery of over 90% of the 2,4‐D added and 75% of the 2,4,5‐T added is obtained. Standard deviations for three formulations are quoted.