Cultivated cotton (G. hirsutum L. and G. barbadense L.) is the leading natural fiber crop. Fiber strength is the main property of the fiber that is limiting in textile processing. Inheritance of cotton fiber strength, as measured by fiber bundles, displays additive quantitative nature. Classical cotton breeding has been successful in improving fiber strength only through the tedious process of selection based on measuring fiber strength in advance generation of the selected lines. Molecular markers in cotton create unprecedented opportunities for improving competitiveness of U.S. cotton production, by targeting genetic changes and accelerating breeding progress. We are currently identifying DNA markers that are linked to fiber strength and other important traits (Glandless, Photoperiod sensitivity, immature fiber, and Ligon lintless-2) in cotton.