Two storage experiments were carried out at Mansoura Horticultural Research Station, Egypt, during the two successive summer seasons of 2007 and 2008. to study the effect of various application techniques (fumigation, dipping and spraying) of natural essential oils; thyme (Thymus vulgaris, Labiatae) and caraway (Carum carvi, Apiaceae) at cold storage (10°C) and ambient temperatures (35/15°C) (day/night) as well as chloropropham (CIPC) on storability, quality and processing of potato (Solanum tuberosum L. cv. Lady Rosetta) . The obtained results revealed that all storage treatments differed significantly in all studied characters. Potato tubers treated with thyme or caraway oils and stored at 10°C or ambient temperature showed the lowest significant values of sprouting and weight loss percents in both seasons of the study. Application of thyme oil at cold storage or ambient temperature resulted in the highest value of dry matter as compared with other treatments, in both seasons. Cold storage had significant effect on reducing sugars and total free amino acids, in both seasons. Tubers of control treatment were of the highest significant gibberillic acid content and of lowest significant abscisic acid followed by cold storage and Chloropropham (CIPC), respectively, relative to all treatments in both seasons. All essential oils/ambient temperature or cold storage treatments gave the best quality processing of chips and French fries, i. e., color, taste and crispiness. Application of caraway or thyme oils by fumigation technique/ambient temperature achieved the highest net return in comparison with other treatments. The study suggests that using thyme or caraway oils by fumigation technique on potato tubers at ambient temperature or cold storage as the best safe, natural, good quality, high-benefit treatments and easy to apply in practice as alternatives to chemical retardants.