Polycyclic aromatic hydrocarbons (PAH) are widespread pollutants produced by incomplete combustion. The city of Krakow in Poland is an industrialized area with high concentrations of PAH in the ambient air. As part of a prospective cohort study being conducted among pregnant women from Krakow, we have measured PAH levels in personal, indoor and outdoor air monitoring over 48-hours collected from 27 women during the 2nd trimester of pregnancy. The monitoring was conducted between January, 2001 and August, 2001. Results show high but variable exposures (ng/m3): Benz(a)pyrene (0.24-36.79); Benz(a)anthracene(0.39-36.69); Benz(b)fluoranthene (0.42-32.64); benzo(k)fluoranthene (0.18-11.25); chrysene (0.34-29.72); dibenz(a,h)anthracene (0.17-9.41); indeno(1,2,3-cd)pyrene (0.55-50.20); pyrene (1.46-47.12). Outdoor PAH levels were higher than indoor levels. Personal levels were lower or similar to outdoor levels and higher than indoor levels. Indoor, outdoor and personal levels were all highly correlated (r>0.93). PAH levels were higher in the samples collected during the winter compared to the summer months. These findings show substantial PAH exposures among cohort women during pregnancy.