The objective of this study was to help in proper understandingof the molecular basis of hemophilia A disease in Egyptianpatients, correlate the genotype with the phenotype and tofacilitate better chance for carrier and prenatal diagnosis infamilies not informative for any of the available genetic markers.The study included 24 unrelated patients with severe hemophiliaA disease. Control group was ten normal persons who had nofamily history of coagulation disease. Screening for hot spots formutations was done using PCR-SSCP (Single strandedconformation polymorphism) for the analysis of six exons infactor VIII gene (exon 2, 8, 18, 22, 23 and 24). DNA sequencinganalysis was done for samples with abnormal electrophoreticmobility in SSCP. A missense mutation (Thr 49 Ala) wasdetected, representing 4% (1/24) of the patients studied. It consistsof substitution of single base (A) by (G) at codon 49 leading tochange of that codon from threonine to alanine. Further studies arerecommended for the screening of mutations in the remainingexons of the factor VIII gene.