This study aims to learn about the effects of pesticide containing Cypermethrin on 45-day-old Penaeus monodon at different temperatures, as indicated through the value of LC₅₀-96h and changes in histology of hepatopancreas. The values of LC₅₀-96h at 22°C, 28°C, 32°C and 36°C were 0,564; 0,345; 0,278; 0,22àg/L, respectively. The histological results showed that hepatopancreas of the shrimp changed significantly as Cypermethrin concentration and temperature increased. The most serious change was at 36^oC, but change severity decreased at 28^oC and 22^oC, and fewer changes were observed at 32^oC. It is implied that hepatopancreas histology of Penaeus monodon is a good tool to assess the toxic properties of the environmental contaminants.