The objective of this study was to determine the infection patterns of etiological agents causing calf diarrhea in the Gyeongnam province, Korea. In this study, from January 2011 to December 2011, feces and necropsy specimens from 249 calves diagnosed with diarrhea (<7 months old) were examined by reverse transcriptase-polymerase chain reaction assay and bacteria & coccidium isolation for detection pathogenic organism. The results of this study showed that 78 cases (31.3%) in spring, 71 cases (28.5) in summer, 62 cases (24.9%) in fall and 38 cases (15.3%) in winter were diagnosed with calf diarrhea, respectively. Calf diarrhea-causing pathogens were diagnosed as bacteria 113 (45.4%), viruses 97 (39.0%), coccidium 1 (0.4%), unknown cases 13 (5.2%), and mixed infections 25 (10.0%). We isolated three virus types from fecal samples (97), which were classified as BVD 64 (66.0%), BRV 21 (21.6%), and BCV 12 (12.4%). Moreover, co-infected pathogens were 25 cases, consisting with BVD & BRV 11 (44%), BVD & BCV& BRV 7 (28.0%), E. coli & BCV 3 (12%), and BVD & IBR 1 (4.0%). In summary, we demonstrated that the enteropathogens of bacteria, viruses, and parasite were detected in samples from cattle with diarrhea, principally in young calves less than 7 months of age. Future studies of infectious diarrhea in cattle should include assays for this etiologic agent.