Secondhand smoke (SHS) exposure has negative effects on maternal and infant health. SHS exposure among pregnant women in Argentina and Uruguay has not been previously described, nor has the proportion of those who have received screening and advice to avoid SHS during prenatal care. Women who attended one of 21 clusters of publicly-funded prenatal care clinics were interviewed regarding SHS exposure during pregnancy at their delivery hospitalization during 2011-2012. Analyses were conducted using SURVEYFREQ procedure in SAS version 9.3 to account for prenatal clinic clusters. Of 3,427 pregnant women, 43.4 % had a partner who smoked, 52.3 % lived with household members who smoked cigarettes, and 34.4 % had no or partial smoke-free home rule. Of 528 pregnant women who worked outside of the home, 21.6 % reported past month SHS exposure at work and 38.1 % reported no or partial smoke-free work policy. Overall, 35.9 % of women were exposed to SHS at home or work. In at least one prenatal care visit, 67.2 % of women were screened for SHS exposure, and 56.6 % received advice to avoid SHS. Also, 52.6 % of women always avoided SHS for their unborn baby's health. In summary, a third of pregnant women attending publicly-funded prenatal clinics were exposed to SHS, and only half of pregnant women always avoided SHS for their unborn baby's health. Provider screening and advice rates can be improved in these prenatal care settings, as all pregnant women should be screened and advised of the harms of SHS and how to avoid it.