This study examined the impact of dietary L-carnitine supplementation on native Egyptian breed (Fayoumi chicken) growth parameters, carcass features, and serum biochemical markers. The present study was performed on 96 male fayoumi chicks divided into four groups each one had 3 replicates each replicate containing 8 chicks, the first group controlled, and the second, third, and fourth groups receive L-Carnitine (25mg/kg, 50mg/kg, 100mg/kg body weight respectively) in drinking water the experiment expanded for 3 months. The birds were weighed at the end of each week. The results demonstrated improvement in feed efficiency (FCR) and body-weight gain (BWG) After 90 days. The obtained results revealed that body weight after slaughtering (bled, de-feathered), semi-eviscerated carcass weight, dressed carcass weight, and breast weight, significantly increased in all treated groups (G2, G3, G4). Each of the Head, liver, heart, and lung weights were recorded and showed a non-significant difference at (P