Cotton yield is integrated through whole-plant and within-boll yield components. Four Egyptian cotton genotypes (Gossypium barbadense L.) were evaluated for within-boll seed yield (boll weight, bolls per plant, and lint percentage) and yield components (seeds per boll, motes per boll, ovules per boll, seed mass, lint mass, and seed-setting efficiency ). The question arises that how do within-boll yield components differ from old cultivars to recent isolated hybrids? Two commercially available cotton cultivars and two isolated hybrids were evaluated in years 2010, and 2011. Ten plants were hand-harvested by fruiting position. Five bolls from first- and second-position bolls from the middle of the fruiting zone were hand-harvested. One of the two isolated hybrids (G.90 x Australian) produced more bolls per plant with more seeds per boll. This also resulted in a greater number of ovules produced boll and a lower number of motes per boll with this isolated hybrid. The greater seeds per boll of (G.90 x Australian) was concomitant with greater seed-setting efficiency compared with the other two cultivated cultivars.