The objective of this study was to determine the fattening performance and carcass traits of Anatolian Merino lambs under different housing systems. Average daily live weight gains (DLW Gain, g), total feed intakes (Total FI, kg) for each stall and the feed conversion ratios (FCR) of Anatolian Merino lambs in indoor and outdoor sheepfolds were found to be 262 and 270 g, 125.2 and 128.8 kg, 4.63 and 4.76 (P>0.05), respectively. The differences between the groups in warm carcass weight (33.07 and 34.90 kg, respectively), cold carcass weight (15.65 and 17.65 kg, respectively), leg weight (2.64 and 2.98 kg, respectively) (P<0.05), dressing percentage (47.32 and 49.61%, respectively) and M. Longissimus dorsi area (12.79 and 16.45 cm, respectively) were significant (P<0.01). Also, the pH (P<0.05), hardness (P<0.05) and the colour values (P>0.05) of the eye muscle area and subcutaneous fat were also determined.