This study was carried out at the nucleus breeding rabbit farm, Poultry Research Center, Faculty of Agriculture, Alexandria University. The main objectives of this study was to evaluate the efficiency of crossing between two lines of rabbits under selection programs on the productive performance of cross rabbits. Three genetic groups of rabbits were used in the investigation. Alexandria line (A) as a synthetic paternal line, V line (V) as a synthetic maternal line and crossing between A line males and V line females (AV). The studied traits used to evaluate productive performance in these three genetic groups were individual body weight at weaning and at marketing age (BW4 & BW9), daily weight gain (DWG), daily feed intake (DFI), feed conversion ratio (FCR), viability rate (VR) and economic efficiency (EE). A total number of 493, 1602 and 1123 from V, A and AV rabbits, respectively were used in the investigation. The results showed that AV cross rabbits were heavier than pure line rabbits (AA and VV) for BW at two ages studied and DWG during fattening period. On other words, AV genetic group attained the marketing body weight earlier than other two groups. Also, the value of FCR improved in AV growing rabbits compared with those obtained for AA & VV rabbits. Moreover, the VR during fattening period in AV rabbits was the highest, while the lowest one was recorded in V line rabbits.  It is clear apparent from these results that, AV group recorded higher values for EE than the other genetic groups. In conclusion, mating between males of the paternal line A and females of the maternal line V gave a cross that saved time and costs in order to reach marketing.