Laminar premixed flames under laboratory conditions often at reduced pressures are of great interest for combustion chemistry and environmental pollution. Recently, there has been considerable progress in studying the combustion of hydrocarbons, oxygenates, and their mixtures. Methods of laser diagnostics, including cavity ring-down spectroscopy and laser induced fluorescence, combined with a number of mass spectrometry techniques for in situ studies of flames allow measurements of concentrations of major species and intermediate products in flames. The structure of fuel molecules and the effect of fuel composition on the structure of intermediate products were studied from the viewpoint of formation of undesired and potentially harmful combustion products in hydrocarbon and oxygenate flames. Chemiluminescence was studied using data on collisional energy transfer. Low-temperature combustion of strongly diluted mixtures in a flow type reactor was investigated.