Rational and Background: Oral disease is an important problem affecting people’s health in Lao PDR, but can be prevented. Pregnant women are more at risk of having oral disease than other groups of people. Oral disease during pregnancy not only affects mothers’ health but also that of babies. Many factors are associated with oral disease during pregnancy, but very few studies were conducted especially in rural areas. Methodology: An analytical, cross-sectional study was carried out from July to September 2012 using close and open questionnaire forms and oral health check up in order to describe oral health status, risk behavior, oral hygiene practice, and factors associated with oral health for pregnant women in three districts of Attapeu Province. Data were analyzed using STATA 10.0 and logistic regression was applied to determine factors associated with oral disease. Results: Five hundred fifty-six pregnant women were studied with a median (range) age of 24 (16-42) years. Most of participants were housewives or famers (78.8%), 62.4% of them with low education level, and 52.0% were Lao-loum (out of 13 ethnic groups). The percentage of the pregnant women who had at least one oral disease was 66.4 %, and the most common oral problems found were dental plaques and carries (53.2% and 10.8%, respectively). Occupation (AOR=2.1 95%CI= 1.4-3.2, P<0.001), ethnic (AOR =2.2, 95%CI=1.5-3.2, P<0.001) and religion (AOR=2.1, 95%CI= 1.4-3.1, P<0.001) were significantly associated with oral diseases during pregnancy. Pregnant women with past and current smoking were 2 times more likely to have oral diseases compared to those who never smoked (AOR=2.1, 95%CI =1.4-3.1, P<0.001). Higher family income (AOR= 0.6, 95%CI= 0.2-0.4, P<0.001) and ANC visits at least once during pregnancy (AOR=0.7, 95%CI=0.5-0.9, P= 0.005) were significant apparent protective factors against oral disease. Conclusion More than half of the pregnant women in rural Laos (Attapeu Province) had at least one oral health problem (mostly dental plaques and carries). Oral diseases were more common in the second than in the first and the third trimester of the pregnancy. Many pregnant women had risk factors associated with oral disease, particularly smoking. ANC visit at least one during pregnancy was associated with less oral disease during pregnancy.