Acute toxicity of hydrogen sulfide to larval stages of white shrimp Metapenaeus monoceros was measured by using the continuous flow through system. Survival rates of white shrimp larvae exposed to hypoxia (≦3.4mgO2ℓ-1) and hypoxia (2.5, 3.4 mgO2ℓ-1) with two different levels of hydrogen sulfide (5, 10 μgSℓ-1) were also determined. The 48hr-LC50 values of hydrogen sulfide were 8.7, 11.4 and 18.5 μpgSℓ-1 for zoea, mysis and juvenile, respectively. Survival rates of zoea, mysis and juvenile exposed to hypoxia were significantly affected by ≦3.4 mgO2ℓ-1, ≦1.5 mgO2ℓ-1 and ≦1.5 mgO2ℓ-1, respectively. Combined effects of hypoxia and hydrogen sulfide were stronger than each single effect. Namely, survival rate was reduced under the combined exposure to ≦3.4 mgO2ℓ-1+10 μgSℓ-1, ≦3.4 mgO2ℓ-1+10 μgSℓ-1 and ≦2.5 mgO2ℓ-1+10 μgSℓ-1 levels to zoea, mysis and juvenile, respectively. From these results, it could be concluded that combined effects of the hypoxia and hydrogen sulfide reported in the coastal region of the Seto Inland Sea, Japan in summer stratification would have affected the larval population of white shrimp in the area.