ABSTRACT. In the recent years, the sheep production in Uruguay has experienced important changes. Every year, lamb meat production has gained significance. For this reason, many efforts are focusing in increase the lamb meat production (growth, reproduction). An alternative for that is the use of non traditional breeds. Four biotypes were evaluated for reproduction performance. The base flock of Polwarth ewes was inseminated with semen from the following breeds:Il de France (IF), East Friesian (EF), Texel (T) and Polwarth or Ideal (I). The EFxI biotype was the group that presented the best reproductive performance in fertility and in twinning rate, of the evaluated biotypes.