The research des ign was a community based crosssectionalrnstudYi it was conducted among second and thirdrntrimester pregnant women by random sampling in Ketchenernarea (previously called Ketchene Awraja) which is part ofrnAddis Ababa city. The obj ecti ve was to determine thernprevalence rate of syphilis and to assess knowledge ofrnpregnant women regarding sexually transmitted diseasesrnwith emphasis on syphilis.rnA total of 410 pregnant women in the second andrnthird trimester from 16 kebeles of the district werernincluded in the study. They underwent a physicalrnexamination, laboratory examinations were done andrnpretested questionnaires were administered in the orderrnmentioned.rnThe study showed that 11% of second and thirdrntrimester women were positive by RPR - blood examinationrntest for treponema palladium syphilis and 7.1% werernpositive by TPHA confirmatory-test for treponemarnpalladium syphilis.rnKnowledge regarding the existence of STDs wasrngenerally high: the percentages who mentioned variousrnSTDs when asked to list those they knew were HIVjAIDSrn(90.2%), syphilis (89.3%), Gonorrhoea (86.8%), chancroidrn(40%) and LGV (20%) respectively. Knowledge regarding thernixrn, Irncauses of STDs is inadequate, particularly with regard torncauses of gonorrhoea, but knowledge regarding treatmentrnand prevention is fair .rnThe frequency of asymptomatic syphilis was high; morernthan half of the 29 TPHA confirmed syphilis cases had nornsymptoms; likewise, the signs/symptoms had a lowrnpositive predictive value, that is very few of those withrnpositive signs/symptoms of syphilis were actuallyrnpositive by the TPHA-test. This may be because they hadrnother STDs (LGV, Chancroid, Herpes genitalis) which havernalso similar clinical manifestations.rnIn this study there was no association between women'srnknowledge regarding STDs and their syphilis status asrnmeasured by the TPHA test.rnIt is recommended to do vaginal examination and swabsrnfor gram stain and wet-mount routinely during antenatalrnand family planning sessions. Screening for syphilisrnusing at least RPR test should be a routine procedure inrnpregnant women.