A series of novel N-(4-aryl-1,3-thiazol-2-yl)-2-(2,4-dioxo-1,3-thiazolidin-5-yl)acetamides (4a-k) and N-(1,3-benzothiazol-2-yl)-2-(2,4-dioxo-1,3-thiazolidin-5-yl)acetamide derivatives (4l-o) are synthesized and evaluated for their anti-inflammatory and antioxidant activity (DPPH radical scavenging, superoxide anion scavenging, lipid peroxide inhibition, erythrocyte hemolytic inhibition). Compounds 4k and 4l have exhibited good antioxidant activity in four assays, while compounds 4c, 4d, 4m, 4n and 4o have shown good DPPH radical scavenging efficacy. Compounds 4a, 4h, 4i, 4k, 4m and 4n have possessed excellent anti-inflammatory activity. N-[4-(o-methoxyphenyl)-1,3-thiazol-2-yl]-2-(2,4-dioxo-1,3-thiazolidin-5-yl)acetamide (4k) and N-(6-nitro-/methoxy-1,3-benzothiazol-2-yl)-2-(2,4-dioxo-1,3-thiazolidin-5-yl)acetamide (4m and 4n) have exhibited both antioxidant and anti-inflammatory activities.