The gas chromatographic profiles of exhaled air from lung cancer patients have been investigated. The breath from healthy volunteers, smokers and non-smokers, and lung cancer patients without treatment and under radio and/or chemotherapy, was collected using Tedlar bags. Different profiles for healthy people and cancer patients could be recognized by multivariate analysis and significant diagnostic compounds could be established. Target compounds showed to be linear and branched hydrocarbons between C(14) and C(24). Solid phase microextraction (SPME) coupled to gas chromatography mass spectrometry GC-(TOF)-MS was used. The method showed good precision (RSD below 26%) and limit of detection ranged from 0.04 to 8.0ppb. These findings show a high potential for establishment of laboratorial screening methods. Validation studies in a larger number of patients are being done.