Small round structured viruses (SRSV) are the major ethological agents which can cause outbreaks of non-bacterial gastroenteritis or food poisoning both in children and adults. The classification of family Caliciviridae to which SRSV belong, is based on the genome encoding three open reading frames. The rotavirus is another major pathogen which causes diarrhea in young children. We examined stool specimens obtained from diarrheal patients in Wonju from which bacterial pathogens were not found. To detect causative viruses from stool specimens of patients, reverse transcription (RT)-polymerase chain reaction (PCR) or nested PCR using rotavirus or SRSV specific primers was performed. In this study, RT-nested PCR procedure which can amplify a 330 bp fragment derived from RNA dependent RNA polymerase (RDRP) region within ORF1 was applied for the detection of SRSV. For the detection of rotaviruses, a 877 bp fragment from the VP4 region of rotavirus genome was amplified. As a result, rotavirus was not detected while SRSV sequences were detected from one out of five specimens. The nucleotide and amino acid sequences of the Wonju isolate were compared with other 6 Korean isolates which have been isolated and sequenced in our laboratory. Sequence analysis revealed that the Wonju isolate was rather distinct from other Korean isolates: the Wonju isolate was closer to genogroup I of SRSV while other 6 Korean isolates belonged to genogroup II.