Replicated tests conducted during three growing seasons (1954, 1955, 1956) at College Station, Texas, have shown that several systemic insecticides (demeton, Am. Cyanamid 12008 and 12009, Thimet and Bayer, 19639) applied as seed treatments adequately protected young cotton plants from thrips for a period of 4 to 6 weeks after the planting date. These materials varied in phytotoxicity which was manifested by reduced emergence or somewhat delayed fruiting under unfavorable conditions for plant emergence and growth. No significant reduction in yield resulted from these phytotoxic effects.