ObjectiveTo investigate Clostridium difficile (C. difficile) infection in hospitalized patients with diarrhea by screening C.difficile in stool specimens and comparing detection rate in different periods.Methods106 stool specimens of inpatients with diarrhea between FebruaryDecember 2009 and AprilJuly 2011 were collected, anaerobic culture and API identification were performed, C.difficile isolates were detected toxin A,toxin B and binary toxin gene by polymerase chain reaction(PCR);enzymelinked fluorescence immunoassay was used for toxin A/B detection.ResultsOf 106 specimens, 16(15.09%) were positive for C.difficile. PCR amplification of toxin A/B were both positive, binary toxin was negative. The positive rate was 12.26% (13/106)by direct detection of toxin A/B,there was no significant difference compared with positive rate of anaerobic culture(χ2=0.16,P>0.05).Positive rate of anaerobic culture was 22.81%（13/57）in February December 2009 and 6.12%（3/49）in AprilJuly 2011, the difference was statistically significant (χ2=5.73,P<0.05);the detection rate of toxin A and B was 17.54%(10/57) and 6.12%(3/49) respectively, there was no significant difference(χ2=3.18,P>0.05). Patients with C. difficile infection used one or more antimicrobial agents,such as cephalosporins, quinolones, carbapenems, broadspectrum penicillin and clindamycin during hospitalization period.ConclusionC. diffilileassociated diarrhea is serious in this hospital, antimicrobial use is an important factor for inducing C.difficile infection.