Background Cervical cancer is the second most common cause of death from cancer among women worldwide.Human papillomavirus(HPV)plays a central role in the etiology of cervical cancer.It is important to describe the prevalence of HPV infection in different types of cervical lesions and to explore the relation between HPV viral load and the severity of cervical lesions.Methods To describe the HPV infection prevalence and viral load in different age groups,we retrospectively investigated 6405 cases of women who were organized by their units to take health-examination.They were given Hybrid Capture ll tests between Janury 2005 and December 2006.The correlation between HPV viral load and pathology was assessed.Results Overall HPV infection prevalence was 29.1%(1864/6405),while in women 18-20 years old it was 54.4% (31/57),the highest among all age groups.After declining rapidly,HPV prevalence stabilized at about 30.0%in women aged 30 and older.Of the 6405 women,1 483 women had a colposcopic biopsy and 33.2%(492/1 483)were positive for HPV DNA.Twenty-one percent of women with a normal diagnosis(238/1 095)had HPV infection,a statistically significantly lower prevalence than in women with cervical lesions,including those with cervical intraepithelial neoplasia (68.8%in CINl,66.7% in CIN2,and 76.5%in CIN3)or with cervical cancer(94.1%).The correlation coefficient between viral load and cervical lesion severity was 0.134,which was not tatistically significant(P=0.075).Viral load values in women with CINs and cervical cancer were calculated,and no significant differences were dentified.Conclusions The revalence of high-risk HPV infection among women attending hospitals for health-examination in Shanghai is similar to the worldwide rate.HPV viral load can distinguish ervical lesions from normal individuals but cannot adequately predict the severity of cervical lesions.