The suitability o f using a commercially available microwave extraction system equipped with a feedback temperature controlling mechanism for high temperature testing o f food packaging materials was studied. The variables studied included sample heatup time, uniformity of temperatures obtained in replicate samples within t h e microwave oven chamber, uniformity of temperatures obtained f o r independent runs under a given set of temperature/ simulant conditions and t h e effect o f glass in t h e test vessels. The food simulants examined were water, 8% ethanol in water, 95% ethanol in water and food oil. The temperatures examined were from 100 t o 175°C. The system used was found t o reach t h e set-point temperatures rapidly (within 5-15 min) and show good temperature reproducibility, b o t h within replicate samples o f a given run and replicate runs. Glass (used typically as spacers in test vessels) was shown to increase the observed temperature variability between samples slightly, but not dramatically. Pressures observed ranged from no increase in pressure for food oil a t any temperature up t o 175°C t o an additional 87 p.s.i. in 95% ethanol a t 135°C (the highest temperature t o which t h e volatile simulants were exposed).