(E)-2-nonenal is considered an important off-flavor of beer, related to the flavor of beer staling. In this study, a new method for determination of (E)-2-nonenal in beer using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS) was developed and applied in Brazilian beer samples. The extractions were carried out in CAR-PDMS (carboxen-polydimethylsiloxane) fiber and the best results were found with 15 minutes of equilibrium and 90 minutes of extraction at 50 degrees C. The method was linear in the range from 0.02 to 4.0 mu g.L(-1) with correlation coefficient of 0.9994. The limits of detection and quantification were 0.01 and 0.02 mu g.L(-1), respectively. 96.5% of recovery and 4% precision (RSD) were obtained in the fortification of beer samples with 2.0 mu g.L(-1) of (E)-2-nonenal. The developed method proved to be simple, efficient and highly sensitive to the determination of this analyte being easily applied in the quality control of the brewery. (E)-2-nonenal was found in all beer samples analyzed with levels between 0.17 and 0.42 mu g.L(-1).301161165