this study performed out during seasons 2016 and 2017 at special farm near Cairo-Alex Desert Road, Egypt, to investigate the effect of dehydration by sun, oven, hot air, oven under vacuum and microwave treatments on some bioactive compounds and their activities in flat (Petrosilinum crispum var. neapolitanum) and curly (Petroselinum crispum var. crispum) parsley varieties cultivated in Egypt. The results showed that yield, ash and acid insoluble ash were the highest in flat parsley than curly, while curly parsley was the highest in total hydrolysable carbohydrates and dietary fiber. The results from bioactive compounds showed that the gradually decrease cosntents of chlorophyll a and b, carotenoids, β-carotene, flavonoids, polyphenols, vitamin C and volatile oil percentage in commercial techniques (sun, oven and hot air dried) and controlling techniques (oven dried 55oC under vacuum and microwave 400W and 800W in either flat or curly parsley. Those results reflected to free radical scavenging activity and total antioxidants activity. Total identified volatile oil components in flat parsley in different dehydration techniques ranged from 11 to 28 items while, in curly parsley ranged from 13 to 28 items. The percentage of total identified components were higher in two parsley cultivars treated by microwave 800W/6 min (66.99 and 66.77%) and 800W/12 min (63.08 and 64.18%) followed by microwave 400W/12 min (58.70 and 56.50%) and 400W/24 min (47.37 and 48.79%) than other treatments either in flat or curly parsley, respectively. the major components of curly leaves essential oil were Myristicin (15.05%), 2-Allyl-4-methyl phenol (10.15%), Isolongipholene (8.59%) and β-Caryophyllene (6.43%).While, volatile oil of flat parsley, the highest compounds were Myristicin (12.65%), 2-Allyl-4- methyl phenol (10.77%), Apiol (9.5%) and Isolongipholene (9.45%). From the obviously results it could be recommended that the best dehydration methods were microwave 800W/6min. > microwave 400W/12min.> oven under vacuum > sun dried > microwave 800W/12min> oven dryer> hot air dried. Finally, through this study, it could be clearly concluded that, it is technical and economical to utilize microwave as a new untraditional dehydration technique in producing flat and curly parsley, rather than traditional dehydration techniques in Egypt, Thus improving the quality specifications of dried parsley which increases the opportunity of exporting.