The aim of this study was to compare HIV-1 prevalence between pregnant, non-pregnant, all women and the general population (men and women) and investigate how well risk behaviours of pregnant women reflect those of all women in the general population in rural Kilimanjaro, Tanzania. A cross-sectional survey involving all individuals aged 15-44 years was conducted in Oria village between March and May of 2005. All consenting individuals were interviewed and offered HIV-1 and syphilis testing. The response proportion among women was found to be 73.7% (914/1241). Age-adjusted HIV-1 prevalence among pregnant women (n = 92) was 32.5% lower (5.4% versus 8.0%, P < 0.001) than that of all women but only 8.5% (5.4% versus 5.9%, P = 0.639) lower compared with that of the general population. HIV-1 risk factors among pregnant women were comparable to that of all women in the general population. In conclusion, pregnant women in the general population underestimate the HIV-1 magnitude among women but closely approximate that of the general population. HIV-1 risk factors are similar between pregnant and all women in the general population. Second-generation surveillance could utilize pregnant women risk behaviours to approximate that of all women in the general population.