This experiment was conducted to several agricultural chemicals such as cuperic sulfate, lime sulfur, swep 80 wp, dithane A-40 and dichlone 50 wp for use as algaecide in wetted nursery of rice, and chemicals were applied at 5 day before and after sowing. The results are summarized as follows. 1. It was found that the effective chemicals as algaecide in wetted nursery were dichlone 50 wp and swop 80 wp, but chemical damage appeared to plant when dithane A-40 and swep 80 wp was applied. 2. Cuperic sulfate was identified to control algae, but it seems to be injurious to seed germination when applied in wetbed nursery. 3. Results were revealed that except dichlone, 50 cuperic sulfate, lime sulfate, swep 80 wp and dithance A-40 decreased the number of roots, rate of dry matter production and plant height compared when no chemical was applied. 4. Dichlone 50 wp was recognized as the most suitable algaecide in view of the plant growth and algae control in wetbed nursery.