Fifty patients with different bullous skin diseases and twenty-five healthyvolunteerswereincludedinthisstudy. Direct immunofluorescent [IF] studies on frozen biopsy sections showed that C3 was deposited in 100% of cases of bullous pemphigoid [BP] at the basement membrane zone [BMZ] , in 64% of cases with pemphigus [P] at the intercellular substance of epidermis and in 20% of cases with dermatitis herpetiformis [DH] at the dermal papillae. IgG deposition was more frequent in P [84%] than BP [78.5%] . Cases withP erythematous demonstrated the presence of an IgG band at the BMZ in addition to the ICS pattern. IgA was detected in four out of five cases with DH, in two cases with P and one case with chronic bullous dermatosis of childhood [CBDC] . Indirect IF showed that anti-skin autoantibodies of the IgG type were found in sera of 58.3% of P cases and in 50% of BP cases. Anti-skin autoantibodies of IgA type were detected in sera of 2/5 cases with DH. Deposition of immune reactants [IgG, IgA and /or C3] occurred at the BMZ of skin in BP, at the intercellular spaces in P and at dermal papillae in DH. The detection of anti-skin auto-antibodies in sera is in favor of the presence of an autoimmune process in such disorders. The study emphasized the importance of IF techniques and their diagnostic applications in bullous skin diseases