In three field experiments at the University of Arkansas Rice Branch Experiment Station, Stuttgart, S-ethyl hexahydro-1H-azepine-1-carbothioate [molinate] at 2, 3, 4, and 6 lb/A was applied into the flood water 3, 6, 11, and 17 days after emergence of rice [Oryza sativa L.] and barnyardgrass [Echinochloa crusgalli (L.) Beauv.]. Molinate at 2 or 3 lb/A applied 3, 6, 11, or 17 days after emergence of rice and barnyardgrass, when weeds ranged from the one-leaf to tillering stages, provided acceptable weed control and rice tolerated these treatments satisfactorily. A rate of 3 lb/A frequently controlled barnyardgrass better than 2 lb/A, and usually was as effective as 4 or 6 lb/A. Sometimes, rates of 4 or 6 lb/A, applied 11 or 17 days after rice emergence, injured the crop moderately to severely and reduced grain yields.