N-(1-Arylethenyl)-2-chloroacetamides were synthesized and their herbicidal activities were tested. Among them, both 2-chloro-N-(2-methoxyethyl)-N-(2-methyl-1-phenylpropen-1-yl)acetamide and 2-chloro-N-(2-ethoxyethyl)-N-(2-methyl-1-phenylpropen-1-yl)acetamide were found to be highly active against upland weeds. In our previous study, it was found that such N-(1-arylethenyl)-2-chloroacetamides as 2-chloro-N-methyl-N-(2-methyl-1-phenylpropen-1-yl)acetamide having no 2,6-disubstituted anilide structure showed high herbicidal activity toward paddy weeds. We have been interested in the structure and herbicidal activity of N-(1-arylethenyl)-2-chloroacetamides. In order to develop highly active herbicides, we attempted to introduce an alkyloxyalkyl or alkenyloxyalkyl moiety.