The current study was carried out at Animal Experimental Station and the Laboratory of Physiology and Biotechnology, belonging to the Animal Production Department, Faculty of Agriculture, MansouraUniversity, during the period from September to December 2014. The aim of this experiment is to study the effect of daily oral administration of free L-canitine (LC) at two levels (350 and 700 mg/h/d) during an experimental period of 63 days on growth performance, rumen and blood parameters, and carcass quality of growing Rahmani lambs. A total of nine Rahmani lambs weighing 33.9±0.69 kg and about 10 months old were assigned according to body weight into 3 groups which were then assigned at random to receive the three experimental treatments. Animals in the 1^st group (G1) were fed the control diet (14.4% CP). The 2^nd and 3^rd groups were fed the same diet, but orally treated with LC at levels of 350 (G2) and 700 (G3) mg/h/d for 63 days as an experimental period. Growth performance parameters, rumen and blood parameters at slaughter and carcass traits were determined. The obtained results revealed that overall feed intake by lambs in G2 and G3 was reduced by about 2.4 and 6.1% as compared to the controls during the whole feeding period. Live body weight of lambs in G2 and G3 was slightly lighter than that in the control group during all intervals of the experimental period. Averages of total and daily body gains of lambs were not significantly affected by LC treatment, although total gain was slightly higher in G2 and slightly lower in G3 than in G1. Feed conversion was almost the best in G2 than in G3 and G1 during feeding intervals or during the experimental period. Ruminal pH value and NH₃-N concentration decreased (P<0.05) in G2 as compared to that in G1, being 6.88 and 8.88 mg/dl, and 7.2 and 17.77 mg/dl, respectively. However, pH value and NH₃-N concentration insignificantly decreased to 7.06 and 13.62 mg/dl in G3, but did not differ significantly from those in G2 and G1. Total VFA's concentration in rumen liquor increased (P<0.05) by about 34.7% in G3 as compared to G1. While, nearly similar VFA's concentration was obtained for G2 and G1 (16.33 mEqui./dl). Only concentration of total proteins in blood plasma decreased (P<0.05) in G2, while triglycerides concentration decreased (P<0.05) in G2 and G3 by about 52.6 and 50.3% as compared to G1, respectively. Concentration of thyroid hormone (T3) insignificantly increased in G2 and G3 (1.95 and 1.68 ng/ml) as compared to 1.6 ng/ml in G1, respectively. The LC had no effect on urea-N concentration in blood plasma. Carcass traits were not significantly affected by LC treatment, although there was an increase in dressing percentage of lambs in both treatment groups (G2 and G3, being 48.13 and 50.94% as compared to 47.93% in the control lambs, respectively. It could be concluded that LC treatment slightly improved feed conversion as a result of improving rumen parameters.