Potato tuber rot is a common and important disease in the world that has been recently occurred in potato fields of Damaneh in Isfahan province. Skins of the infected tubers are usually cracked and darken cavities containing nematodes are observed in the tuber flesh. In some cases, affected tubers had soft rot symptoms with brown margins as described for pectolytic bacteria. To identify the pathogens involved in the development and spread of potato tubers rot in the region, a large number of rotten potatoes were collected from the potato fields of Damaneh between 2009 and 2010. Microscopic examination of the cracked skin tubers showed the presence of many nematodes in white pockets of flesh of these samples. The majority of nematodes found in the pockets were identified as Ditylenchus destructor based on morphological and morphometric characters . PCR tests using general primer rDNA1/rDNA2 yielded a DNA fragment length approximately 950bp corresponded to ITS region of the nematode samples. The TaqI digestion of 950 bp fragment revealed the genetic homology among ITS region of the strains of D. destructor collected from Damaneh. Sequence analysis of this fragment and its alignment with the sequences deposited in NCBI database indicated that the ITS sequences of the nematode causes potato tuber rot in Isfahan has significant homology (99-97%) with the sequence of D. destructor isolates reported from various countries. Fifteen pectolytic bacteria with green metallic colonies on EMB medium were isolated from the tubers showing surface cracking and soft rot symptoms, simultaneously. All the isolates grew at 36 ?C, were resistant to erythromycin, negative for phosphatase, indole production, production of reducing substances from sucrose, xylose, trehalose, ?-methyl D-glycoside, palatinose and malonate, while positive for acid production from inositol, ramnose and arabitol. Based on These characteristics the isolates recognized as P. carotovorum su. carotovorum . The isolates were further identified by PCR amplification with primer G1/L1 which produces two bands similar to those produced in P. carotovorum su. carotovorum, but not from P. carotovorum su. atrosepticum and Dickeya chrysanthemi . Digestion of the amplified PCR product with restriction enzyme Rsa I resulted in identical bands formation as described for P. carotovorum su. carotovorum. The results of physiological, pathogenicity, biochemical and molecular tests, confirmed that all bacterial isolates induced soft rot symptoms in potato tubers are P. carotovorum su.