The extent and nature of physio-chemical changes that take place in detached leaves after harvest and during storage have been reviewed and discussed by Osborne (1962) and Rogers (1955). These changes include loss of moisture (Wittwer et al., 1962), chlorophyll degredation (Person et al., 1957), Protein loss (Thimann and Manmahan, 1960), and result in subsequent appearance of the visual manifestations of senescence of plant tissues. As lettuce, like most leafy vegetables, deteriorates rapidly and steadily after harvest. Loss of quality is inevitable and can only be minimized by rapid handling and with the best possible storage conditions (Pratt et al., 1954). In recent years, abundant work has been done to delay senescence by the use of various chemicals. Among the investigated chemicals, kinetin (6-furfurylarninopurine) and its related c ompounds show some promise. Van Overbeek et al. (1941) reported a potent new growthpromoting factor (kinetin) in coconut milk. This chemical is active in causing many of the growth reactions of c oconut milk at exceedingly small dosages. Subsequently several arninopurine compounds were synthesized. One of which is SD 4901 (Verdan), N6-benzyladenine, an experimental senescence inhibitor, was developed by Shell Development Company, Modesto, California in 1960. Many reports showed that this chemical is capable of delaying senescence of plant tissues on the basis of restoring protein molecules and respiration inhibition. On the other hand, others have shown stimulation of respiration and delaying of senescence. Paucity of scientific literature on the stability of those chemicals on leafy vegetables gave impetus to a study of the comparative influence of pre- and post-harvest applications of 6-furfurylaminopurine and N6-benzyladenine as related to successive harvest times. Such studies may have considerable economic bearing upon storing and shipping leafy vegetables to distant markets. This thesis presents effects of different concentrations (5, 10, and 20 ppm.) of pre- and post-harvest applications of 6-furfurylaminopurine and N6-benzyladenine as related to three successive harvest times (at one week intervals) on chlorophyll content, moisture content, total nitrogen, insoluble and soluble nitrogen, oxygen uptake, 0 and co2 production during storage (at 40 Fo and 85 percent RH) of "Great Lakes" variety of lettuce.