The present study was conducted to investigate the effect of feeding commercial probiotic preparation (Proact) supplementation on growth performance, carcass traits, blood parameters, intestinal morphological parameters and economical efficiency. A total of 240, one-day old Molar ducklings were individually weighed, wing- banded and randomly assigned to eight equal groups each of 3 replicates (30 birds each). All birds were fed a starter diet until 21- day of age and finisher diet from 22 day until marketing (70 d). Ducklings of group 1 (control) were fed the starter and finisher diets without Proact supplementation. Ducklings of groups 2, 3, 4, 5, 6, 7 and 8 were fed the control diets plus graded levels of Proact (0.25, 0.50, 0.75, 1.00, 1.25, 1.50 and 1.75g/ kg diet, respectively). Results revealed that ducklings of group 4 (0.75) showed significantly (P≤ 0.05) higher body weight, body weight gain, feed intake and performance index. Moreover, feed conversion ratio, European efficiency index and economic efficiency were significantly improved. Carcass and giblets weights and percentage were significantly (P≤ 0.05) increased with the supplementation. Probiotics supplementation (0.75g/ kg diet) significantly increased serum glucose and liver enzymes (AST and ALT), and significantly (P≤ 0.05) decreased createnine, cholesterol, triglyceride and total lipids. However; total protein and albumen were not affected.  Moreover, villi height, villi width and villi height: villi width ratio were significantly improved by the addition of probiotics up to 0.75g/ kg diet. Therefore, it may be concluded that supplementation of 0.75g probiotics/ kg diet could be used in diets of Molar ducklings from 0-10 weeks of age to improve growth performance, feed efficiency, and carcass traits.