There is growing concern over the widespread exposures to phthalates detected in the U.S. population. Phthalates have been shown to be hepatic, reproductive and developmental toxicants. Certain phthalates are elevated in women of reproductive age, resulting in implications for the health of the developing fetus. In the current study, we assess the presence of phthalates in personal air samples of pregnant women subjects in prospective cohorts in Northern Manhattan and Krakow, Poland. Phthalates were detected in 100% of samples. Diethyl phthalate (DEP) (range 1,447-7,123 ng/m3) and dibutyl phthalate (DBP) (range 755-14,763 ng/m3) were present at the highest levels in Northern Manhattan and Krakow respectively. Dicyclohexyl phthalate (DCHP), butylbenzyl phthalate (BBzP), diethylhexyl phthalate (DEHP), and disobutyl phthalate (DIBP) were present in ascending order. Demographic characteristics of study subjects are presented to identify possible risk factors. Comparison data are presented for 4 phthalate isomers to assess the significance of these levels.