This study was carried out to determine the production levels of Turkish Merino (Karacabey Merino) lambs for birth weight, weight at weaning and at first year of age and greasy fleece weight at first shearing and to investigate the effects of the measurable environmental factors affecting on these characteristics. The birth weight was 4.83 kg, weight at 90lh day of age was 32.14 kg, weight at first year of age was 57.59 kg and greasy fleece weight at first shearing was 6.36 kg for Turkish Merino lambs. The effects of birth year, dam's age. birth type and sex on birth weight, weight at weaning (90lh day) and at first year of age and the greasy fleece weight at first shearing were found to be statistically significant. Also the interactions of year x dam's age and year x dam's age x birth type on birth weight; year x dam's age x birth type on weight at weaning; year x dam's age and year x sex on weight at first year of age and year x dam's age and year x sex on greasy fleece weight were found to be affecting significantly. By taking the effect shares of the factors affecting on these characteristics into consideration the production data of the lambs can be corrected and so the effectiveness of the different selection methods, which will be applied in the forthcoming years in the institute on Turkish Merino, might be improved.