The aim of this study was to determine the proportion of income resulting from live body weight gain and from difference between the purchase and sale prices of lambs in the total income. Forty male, weaned Kivircik lambs (90 day-old) were randomly and equally allocated to five groups at a mean weight of 26.7 kg. During the study (84 days), experimental groups were fed diets which contained different levels of dietary crude protein (10, 12, 14, 16, 18%). Initial live-weight of lambs were 26.2 kg, 26.6 kg, 25.6 kg, 28.0 kg, 27.5 kg, respectively; final liveweight of lambs were 40.1 kg, 41.8 kg, 42.3 kg, 45.0 kg, 43.1 kg, respectively; total live-weight gain of lambs were 13.9 kg, 15.2 kg, 16.7 kg, 17.0 kg, 15.6 kg, respectively; price margins were 3.00%, 2.81%, 2.46%, 2.65%, 2.83%, respectively; weight margins were 97.00%, 97.19%, 97.54%, 97.35%, 97.17%, respectively. Average initial live-weight, average final live-weight, average total live-weight gain, average price margin and average weight margin were 26.78 kg, 42.46 kg, 15.68 kg, 2.74% and 97.26%, respectively. As a result of this study, it was indicated that great part of income of enterprise was obtained from live weight gain.