Among a health cooperation project, we had the opportunity to study the internal polycyclic aromatic hydrocarbon (PAH) exposure of residents from urban and rural areas in Afghanistan. Urine samples from 13 children (age 2.0-9 years) and 42 adults (age 20-65 years) were collected. A total of 25 participants were from Kabul, and 30 participants lived in a rural area. The determination of 1-hydroxypyrene and hydroxyphenanthrenes was carried out by high performance liquid chromatography and fluorescence detection. Median (range) were as follows (n=55): 1-hydroxypyrene 1646 ng/l (71-16,288 ng/l) and sum of 1-, 2- and 9-, 3-, 4-OH-phenanthrenes 3602 ng/l (116-19,670 ng/l). These results indicate a high PAH exposure, compared with the general population in more developed countries. The levels of 1-hydroxypyrene in urine of women (all non-smokers) from the rural area were higher than those from Kabul (N, median, range): rural 15, 2095, 334-11,357 ng/l; Kabul 11, 748,137-5332 ng/l. All households from the rural area used open fires for cooking and energy. We conclude that populations in low-developed countries may be at special risk to increased PAH exposure due to inadequate control of air pollution from car emissions and due to burning of biomass fuels for cooking and household energy.