The effects of different water management and herbicides on grain production and physiological quality of rice seeds, were studied during three growmg seasons, namely, 1978/79, 1979/80 and 1980/81 at UEPAE de Pelotas-EMBRAPA, state of Rio Grande do Sul, Brazil. The experiments were carried out at field conditions using sandy soil with a wilting point of 5,7% and field capacity of 15,5%. The Bluebelle was the cultivar used to evaluate the parameters studied. The water management treatments consisted of three irrigation periods, at 20, 30 and 40 days after rice emergence and three periods of final drainage, namely 20, 30 and 40 days in 1978/79; 15, 25 and 35 days in 1979/80 and 10, 20 and 30 days in 1980/81, after the begining of the heading stage. The herbicide treatments were: Molinate, Butachlor and Propanil plus Thiobencarb applied at rates of 3.6, 3.6, and 1.6 + 3.2kg/ha a.i., respectively. Results indicated that the herbicide Butachlor reduced the initial stand of rice but did not cause damage to the final grain yield. According to the results obtained, it was concluded that the begining of irrigation should be 30 days after rice emergence and that the drainage periods tested had not influence on grain yield. Physiological quality of rice seeds was not affected by the herbicides and drainage periods, but it was affected by irrigation initiated at 40 days after emergence, reducing germination and vigor of harvested seeds.