During the pyrolysis of cured phenolic resins, the bridges between the phenolic nuclei are destroyed. Besides other decomposition products, phenol is produced as well as its methyl-substituted homologues. These phenolic decomposition products are easily identified by gas chromatography and their amounts determined. This enables conclusions to be drawn as to the composition of the resins. This is of interest above all because cured phenolic resins are almost impossible to analyze by other methods. Results of an experimental investigation are presented and discussed in terms of decomposition mechanisms of phenolic resins.