Between February 2011 and February 2012, 985 and 324 samples were collected from diarrheal and healthy pigs, respectively, to detect porcine epidemic diarrhea virus (PEDV), porcine kobuvirus (PKoV), porcine bocavirus (PBoV), porcine group A rotavirus (GARV), and transmissible gastroenteritis virus (TGEV). PEDV and PKoV clearly predominated in diarrheal pigs. Compared to healthy pigs, a substantial prevalence of mixed infections was observed in diarrheal pigs (72.3 %) (P < 0.001). All of the coinfections were grouped into 13 patterns. The results of quantitative PCR showed PEDV in diarrheal pigs had a slightly higher mean viral load than that in healthy pigs (7.9 × 10(6) versus 2.0 ×10(5) copies/g of stool), while similar mean viral loads were observed for PKoV and PBoV. These findings reveal the severity of coinfections in diarrheal disease and suggest that attention should be paid to synthetic administration and vaccination for its prevention and control.