Volatile organic compounds (VOCs) and nitrogen oxides (NOx) released from petrochemical industry facilities and auto vehicles are known to be responsible for rapid photochemical ozone (O3) production in the Houston Metropolitan (HM) area. Specified VOC measurements facilitate understanding of the atmospheric processes leading to high O3 (> 80 ppbv) episodes in the HM area and, hence, are important to develop efficient yet economical emission control strategies. During the TexAQS II 2006, a proton transfer reaction mass spectrometer (PTR-MS) was deployed at two observation stations (the Moody Tower of the University of Houston and the Aldine site) from August 17 to October 15, 2006 to conduct specified VOC measurements. Fourteen individuals or groups of VOCs were monitored during the campaign including acetonitrile, propene, acetaldehyde, butenes, acetone, acetic acid, isoprene, MVK+MACR, MEK+MGLY, benzene, toluene, C2-benzenes, C3-benzenes, and mono-terpenes. Propene and butenes were identified as the major alkene species observed during the campaign and showed influences from the ship-channel petrochemical industry area. Aromatic VOCs were dominated by automobile emissions. The averaged benzene/toluene ratio was 0.15. Isoprene and monoterpenes showed both biogenic and industrial sources. VOCs observed at Aldine correlated well with organic aerosol measurements, which might indicate that oxygenated VOCs participate in the secondary organic aerosol formation.