ABSTRACT Community-acquiredpneumoniaisacommondiseaseandafrequentcauseofmorbidityandmortalityworldwide.HaemophilusinfluenzaeisaleadingcauseofCAP.ThecurrentstudywasconductedtodeterminetheserotypedistributionandantimicrobialsusceptibilitypatternsofHaemophilusinfluenzaeisolatedfromunvaccinatedadultpatientswithCAPatAssiutUniversityHospitals.MaterialsandMethods:FromSeptember2013toaugust2014,sputumsamplesfrom132adultpatientswithCAPwereanalyzedforthedetectionofHaemophilusinfluenzausingconventionalmethods.AntimicrobialsusceptibilityandserotypingofHaemophilusinfluenzaewasperformed.Results:Haemophilusinfluenzaeweredetectedin21(16%)CAP-patients.Non-typeableHinfluenzaewerethemostfrequentlyisolatedserotypethatfoundin15(71%)ofHinfluenzae-cases.Hinfluenzaetypebwasfoundin5(24%)cases.WhileHinfluenzaetypefwasfoundinone(5%)case.CasesweredetectedmainlyduringJanuary,February,andMarch.ResistancewashighestfortheB-lactamgroupofantibiotics.Conclusion:CAPhasadiseaseburdeninadultpatientsatAssiutUniversityHospitals,Egypt.HinfluenzaeisaleadingcauseofCAPwhichwasassociatedmostlywithnon-typeableserotypes.ResistancetopenicillinandotherantimicrobialagentsincreasedrapidlyduringthelastyearsamongH influenzaestrains. Keywords:Haemophilusinfluenzae,community-acquiredpneumonia,serotyping, antimicrobialresistance.