Polycyclic aromatic hydrocarbons were detected in groundwater of Al-Qassim region of central Saudi Arabia. Water samples from sixteen wells of different depths located at varied site were analyzed spectrophotometrically. The three fundamental bands characteristic of aromatic hydrocarbons nuclei at 240 – 250 nm were recorded.  However, the very slight difference in absorption is due to solvent interaction as the medium analyzed is an aqueous solution. Wavelength shifts towards longer wavelength due to fusion of aromatic nuclei in polycyclic systems around 280 nm were also observed. The data were discussed in relation to the possibility of contamination by direct mixing of sewage water with underground water and/or leaching of agricultural chemical fertilizers and pesticides with rainfall or irrigation water down through sandy soil particles to reach the underground water bed.