The economic justification for increasing lamb production in semi-intensive Awassi flocks, by introducing the Afec-Awassi strain that carries the Ballele of the FecB (Booroola) locus, was studied, taking into consideration different breeding methods for high prolificacy and different economic environments. In the analysis, the production process was defined as a series of tasks, each job which can be accomplished by one or more alternative techniques. Under the range of economic parameters tested, introduction of the Afec into Awassi flocks managed under semi-intensive conditions would be profitable in most scenarios. The higher the ratio between lamb price and feed costs, the greater the benefit from the use of the Afec. Furthermore, selection of replacements based on the genotyping of ewe lambs for carrying markers linked to the FecB gene is economically justified in all cases.