Gas chromatographic analysis of volatile fatty acids (VFAs) in mixtures of swine manure and sawdust and in condensate samples of gasses emitted during composting of these mixtures was conducted. Two pilot-scale composting runs were conducted in a total of 11 vessels under either continuous or intermittent aeration. Initial pH below 6 in two of the vessels corresponded to slower onset of composting and greater release of VFAs over extended periods. Otherwise, composting began rapidly, and VFA emissions took place primarily in the first four days of the process. In all the vessels, total emissions were less than 1% of the initial VFA contents of the material even though final values for these contents were reduced by 95 to 100%, except for the two low pH vessels where reductions ranged from 51 to 93%, and except for isobutyric acid where 90% reductions were typical. Intermittent aeration (at a total air flow reduction of 76%) reduced emissions of acetic, propionic and butyric acids by 68, 68 and 33% relative to continuous aeration, but isobutyric, isovaleric and valeric acid emissions were increased by 151, 8 and 17%, respectively. Thus, composting, particularly when initial pH was >=6, rapidly destroyed odorous compounds while they were still in the mixtures, and, even though the odor potential is high, particularly for butyric and valeric acids, it seems that composting with low air flow aeration has the potential to reduce odor problems.