There have been few published reports regarding surveillance of individuals occupationally exposed to 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). The present study examined the mortality experience of 204 persons exposed to 2,4,5-T during its manufacture from 1950 to 1971. Length of employment in job assignments within the 2,4,5-T process area ranged from less than one year to a maximum of approximately ten years. Efforts to minimize 2,3,7,B-tetrachlorodibenzo-p-dioxin (TCDD) contamination of the product resulted in nondetectable concentrations using a method of detection developed in 7966 that was sensitive to 1 part per million. Within the scope of this mortality survey, no adverse effects were observed with respect to occupational exposure to 2,4,5-T or its feedstock, 2,4,5-trichlorophenol.