The aim of this study was to develop and assess the physicochemical stability of umbu-caja diet jams during storage under ambient conditions. Five jam formula- tions were prepared, with varying concentrations of aspartame (0.055, 0.065 and 0.075%) and low methoxyl pectin (0.5, 1.0 and 1.5%). In addition to umbu-caja pulp, edulcorant and pectin, calcium chloride and potassium sorbate were used. The formulations were concentrated in an open saucepan until reaching total soluble solids (TSS) of 12.5°Brix, transferred to glass containers and stored at mean temperature and relative humidity of 23.25C and 81%, respectively, with physicochemical analyses at day 0 and every 30 days of storage up to 180 days. It was found that storage did not cause significant alterations in the relative humid- ity, total solids, water activity, TSS and extrusion. Data related to total soluble solids/total titratable acidity (TSS/TTA), pH and hardness increased significantly, whereas TTA and color parameters were reduced. Moreover, the jams were consid- erably darkened at the end of storage.