The effect on deposit formation rate of the presence of trace amounts of nitrogen and oxygen containing impurities in deoxygenated JP-5 was investigated. The change in deposit formation rate, following the addition of representative nitrogen and oxygen compounds, was determined over a temperature range of 150-450 °C in fuels with molecular oxygen contents reduced to less than 1 ppm. The addition of nitrogen compounds as pure materials did not increase deposit formation over the temperature range studied. However, certain nitrogen compounds led to sludge formation at temperatures in the range of 20-25 °C. Of the oxygen compounds studied, peroxides as a class were found to be highly deleterious to fuel stability. Some acids, esters, and ketones were moderately deleterious while others had no significant effect on deposit formation. In general, cycloalkyl compounds were less harmful than their aliphatic or aromatic counterparts. Several interactions between trace impurities were discovered which affect deposit formation rates.