Antioxidant is an interesting molecule which has been studied world wide for human health. The aims of this study are to screen the Total Phenolic Content (TPC) and antioxidant activity of sericin extracts from 5 varieties of Eri silk. In addition, domesticated Thai silk; Nanglai and Dokbua were also investigated in comparison. The sericin was firstly extracted by warm distilled water. The TPC of each silk variety was determined using Folin-ciocalteu assay. The results indicated that domesticated silk have higher TPC than all of Eri. DPPH radical scavenging and Ferric Reducing/Antioxidant Power (FRAP) were used for measurement the antioxidant activity of the sericin extracts. The results found that domesticated Thail silk had higher antioxidant capacity than that of Eri but with different values. The results suggested that TPC and antioxidant of the sericin extracts exhibited good correlation. This means the TPC is main factor for antioxidant capacity. However, the variation of both TPC and antioxidant of sericin extracts were influenced by silk varieties. Moreover, domesticated Thai silk composed of some pigments which are antioxidant compounds. However, Eri silk should be considered as alternative sources for antioxidant. © 2011 Asian Network for Scientific Information.