Objective   To understand the sexual and reproduct ive health(RH)knowledge statues of male and female unmarried migrants aged 15~24 and its influencing factors.

  Methods   1 092 unmarried migrants aged 15~24 were investigated with anonymous self administered questionnaire in Changning District, Shanghai,

  Results   The knowledge scores of male and female unmarried young migrants were rather low with the median score being of 53.2 and 30.5, respectively.Malesad more knowledge, with the median score higher than that of females by over 20.Whether they were males or females, the knowledge of sex ual physiology and contraceptives was lower than that of sexually transmitted disease(STD)and HIV/AIDS.Knowedge scores of both males and females were positively influenced by education level, going out to work alone, having received sexual educationg at school and having communicated sexual knowledge with others.When looking at gender disparity, for males, age and having watched prnographic videos were also positively associated with knowlege.In contrast, for females, former residence(urban/rural), income per month, living with lovers, having communicated sexual knowledge with parents and media wree positively associated with know ledge.

  Conclusion   The differences of sexual knowledge and related factors between males and females should be considered when sexual and RH education and services are provided to unmarr ied young migrants.