Abstract: Soils of Pakistan are frequently characterized as deficient in plant-available phosphorus (P). The option of fertilizer applications to cope the situation has proved cost-intensive for resource-poor farmers of the country. Under the circumstances, exploitation of genetic variations in crops for P-use efficiency and identification of P-efficient crop cultivars hold great promise. Experiments conducted at the University of Agriculture, Faisalabad indicated significant growth differences among varieties of wheat, rice, chickpea and cotton when grown under P-deficient as well as P-adequate conditions. Differences in relative adaptability of varieties to P-deficiency stress were also considerable. In this paper, work done in Pakistan and elsewhere on genotypic variations of P-nutrition of crops is briefly reviewed. Various physiological mechanisms responsible for such variations are also discussed.