The objective of this study was to evaluate yielding ability of six bread wheat lines and cultivars under wide range of environments. The trials were conducted for the two growing seasons (2003/2004 and 2004/2005) in five main locations, namely El-Nubaria (New lands, West Delta), EI-Gemmeiza and Kafr El Hammam (South Delta), Sids (Middle Egypt) and Shandaweel (Upper Egypt). The study revealed that the two common cultivars Giza 168 and Sakha 93 were the highest yielding ones , with regression slopes over environment not exceeding unity and considerable deviation from regression that pertain considerable stability over wide range of environment representing the main regions of Egypt . Other genotypes proved high level of stability but very humble productivity. The superiority of the two cultivars was related to the longest grain filling period, highest grain and straw yields / feddan. Therefore, growing these two cultivars Giza 168 and Sakha 93 allover Egypt is highly recommended.