Di-octyl phthalate(DOP) is widely used as a plasticizer in the plastics industry.As a result,DOP is often found in marine water ecosystems where many species are exposed to it.Our objective was to evaluate the effect of long-term(14 d) DOP exposure(2.6,7.8,or 31.2 mg/L) on the expression of immunerelated genes in Tegillarca granosa.The expression of small heat shock protein(sHSPs) and tissue inhibitor of metalloproteinase(TIMP) were highest in clams exposed to 31.2 mg/L DOP on days 7 and 14.The relative expression of Tg-ferritin,superoxide dismutase(SOD),and metallothionein(MT) increased initially then decreased as the concentration of DOP increased.The hemoglobin of T.granosa(Tg-Hb I) exhibited two distinct expression patterns at two time points.Our results suggest that the immune response of T.granosa against DOP pollution varies depending on the dose.Additionally,we identified some immune-related genes that are promising candidates for biomarkers of DOP. Di-octyl phthalate (DOP) is widely used as a plasticizer in the plastics industry. As a result, DOP is often found in marine water ecosystems where many species are exposed to it. Our objective was to evaluate the effect of long-term ( 14 d) DOP exposure (2.6, 7.8, or 31.2 mg / L) on the expression of immunerelated genes in Tegillarca granosa. The expression of small heat shock protein (sHSPs) and tissue inhibitor of metalloproteinase (TIMP) were highest in clams exposed to 31.2 mg / L DOP on days 7 and 14. The relative expression of Tg-ferritin, superoxide dismutase (SOD), and metallothionein (MT) increased initially then decreased as the concentration of DOP increased.The hemoglobin of T.granosa (Tg- Hb I) showed two distinct expression patterns at two time points. Our results suggest that the immune response of T.granosa against DOP pollution varies depending on the dose. Additionally, we identified some immune-related genes that are promising candidates for biomarkers of DOP .