The performance of purebred Romanov (R) lambs and crossbred lambs of Romanov and Morkaraman (M) breeding were compared under a semi-intensive production system. The M breed is a fattailed breed native to Eastern Anatolia, Turkey. Analyses were conducted on data from 168 lambs produced from R and M ewes through laparoscopic artificial insemination (LAI) with the semen of pure R and F1 RxM rams. Pure R, F1 (RxM, ½ R), and ¼ R (RxM x M backcross) lambs were produced. The F1 and ¼ R lambs had heavier (P < 0.05) birth weights than R lambs while F1 and R lambs had heavier (P < 0.05) weaning weights than ¼ R lambs. The three groups of lambs differed (P < 0.05) from each other for age of puberty in males and females where with R lambs were the youngest, F1 lambs were intermediate, and ¼ R lambs were the oldest. The percentage of ewe lambs that exhibited estrus within one year of age was higher (P < 0.01) for R (100%) and F1 (67%) lambs than for ¼ R lambs (43%). In conclusion, improvement in growth and early reproductive traits can be obtained from crossbreeding the fat-tailed Morkaraman breed with the Romanov breed.