The effects of fair treatment on saliva cortisol release of low and high Type-A behavior participants in high or low stress conditions are studied. Based on the Injustice Stress Theory (Vermunt & Steensma, 2001), predictions were made about fair treatment as a stress reducing factor. The results support the expected effect of fair treatment in that high type-A behavior participants in the low stress conditions had lower saliva cortisol levels after fair treatment while this effect was absent in the neutral condition, while low type-A behavior participants showed lower saliva cortisol release in the high stress conditions after fair treatment while this effect was absent in the neutral condition. Moreover, saliva cortisol scores are correlated positively with negative affect scores and negatively with positive affect scores. The discussion focuses on theoretical implications and suggestions for future research.