Rhizoctonia solani is the biological causal agent of the potato black scurf disease. The symptoms were examined on vegetative and tuber potato plants in eight Egyptian governorates (Aswan, Behera, Dakahlyia, Gharbia, Giza, Ismailia, Menofyia, and NewValley) during 2012-13 and 2013-14. Representative infected samples of Diamant, Hermes, Lady Rosetta and Spunta cultivars were collected randomly from different conventional and organic farms. Field survey produced a total of 182 isolates. The highest disease severity occurred in Ismailia and Behera, while the lowest severity was in Menofyia. The cultivar Herms was resistant in greenhouse and field trials, while Lady Rosetta was the susceptible. Disease incidence and severity were higher in organic than conventional cultivation farms. The 182 isolates were subdivided into 14 group based on the morphological examination. The anastomosis test on 50 selected isolates produced four different interactive groups (C0-C3). Sequence analysis was performed on the internal transcribed spacer (ITS) 18s rDNA of 35 selected isolates and confirmed the identified groups. High molecular similarity and single nucleotide polymorphisms (SNP) were produced between the representing ITS sequences of the (AG3, AG4, AGA, and AGF) groups using the comparative analysis. The AG3 and AG4 groups included 25 and six isolates; respectively, and severely infected potato. The AGA and AGF groups included three and one isolates; respectively, and unregistered for potato invasion. These results of great applications at the level of potato black scurf disease characterization in Egypt.