The genus Armillaria contains white-rot basidiomycetes pathogenic to woody plant hosts worldwide. Of particular interest are the species found in southeastern peach (Prunus persica) orchards causing Armillaria root rot. Isolates collected during the past four years from orchards in Georgia, South Carolina, and Alabama were identified to species and grouped within species based on molecular analysis of the internal transcribed spacer (ITS) regions and the intergenic spacer (IGS) regions of the ribosomal DNA (rDNA). Thirty isolates of A. tabescens and nine isolates of A. mellea were identified from these orchards. Restriction fragment length polymorphism (RFLP) analysis of the IGS region with Alu I revealed two groups of A. tabescens and one group of A. mellea. Similarly, the ITS region was amplified with primer sets At- ITS1/Am-ITS1/ITS-2 and ITS-1/ITS-4 and subsequently restricted with Mbo II and Hha I. These restrictions indicated two groups of A. tabescens and four groups of A. mellea.