The main aim of the study was qualitative and quantitative analysis of volatile organic compounds (VOCs)occurring in biological samples such as exhaled air obtained from 108 patients with lung cancer, 121healthy volunteers, and 24 persons with other lung diseases. For determination of VOCs in human breath,solid phase microextraction and gas chromatography–mass spectrometry (SPME/GC–MS) were applied.Statistical methods such as artificial neural network and chi-squared automatic interaction detector(CHAID) were applied for data evaluation. The concentration of acetone, isoprene, ethanol, 1-propanol,2-propanol, hexanal, and dimethyl sulfide were higher in patients with lung cancer than in case of healthyvolunteers and persons with other lung diseases.The second goal was the application of trained dogs for detection of the same breath samples as inGC–MS research and evaluate the sensitivity and specificity of canine scent detection using 5 stationscent lineup. Among lung cancer patients and complementary samples, overall sensitivity of canine scentdetection was 86%, while specificity was 72%.There is a possibility that in the future these methods could allow for a fast, painless, and noninvasivediagnosis of cancer.