This study was carried out to evaluate the effects of dietary supplementation of purslane powder (PP) on performance, blood indices, and antioxidant status in broilers with triiodothyronine (T3)-induced ascites. In total, 240 one-day-old male broiler chicks (Ross 308) were randomly assigned to four treatments, with four replicates per treatment and 15 birds per replicate. The experimental diets included (i) a control diet, (ii) a control diet plus 1.5 mg kg−1 of T3 (T3 diet), (iii) a T3 diet with the addition of 1.5 g kg−1 of PP, and (iv) a T3 diet with the addition of 3 g kg−1 of PP. Feed intake and body weight were measured at 10, 24, 39, and 49 days of experiment. Blood and liver samples were collected from two birds in each replicate at 24 and 49 days of experiment. The T3-treated birds had higher (P < 0.05) right ventricle to total ventricle (RV / TV) ratio and mortality due to ascites compared with the control. In addition, during the entire experimental period (0 to 49 days of experiment) the T3-treated birds had lower (P < 0.05) feed intake, body weight gain, and production efficiency index and higher (P < 0.05) feed conversion ratio compared with the control. Dietary supplementation of PP reduced (P < 0.05) mortality due to ascites and RV / TV ratio, while the production efficiency index was increased (P < 0.05) by the addition of PP to the diet. The T3-treated birds had higher (P < 0.05) red blood cell counts, hematocrit percentage, and hemoglobin concentration compared with the control at 24 and 49 days of experiment. Dietary supplementation of PP substantially alleviated (P < 0.05) the negative effects of T3 on hematocrit and hemoglobin values at both 24 and 49 days of experiment and on red blood cells counts at 49 days of experiment. The T3 birds showed an increase (P < 0.05) in activities of lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase at 49 days of experiment. However, the detrimental effect of T3 on alanine aminotra