Eighteen plum/prune preparations and byproducts were analyzed for proximate constituents and carbohydrate profiles. Plum puree and prune juice contained the highest concentrations of ash (13.0 and 13.8%, respectively). Crude protein (CP), acid-hydrolyzed fat (AHF), and total dietary fiber (TDF) concentrations were higher in byproducts (waste cake and dried plum pits) compared with the other fractions. Several classes of oligosaccharides were found in low concentrations in many of the substrates and were associated with the fruit rather than the pit. Maltooligosaccharides were found in very high concentrations in three of the preparations as a result of the addition of maltodextrin during processing. Monosaccharides, sugar alcohols, and oligosaccharides were found in higher concentrations in the fruit than in the pit and accounted for 2.9-84.7% of substrate organic matter. These results indicate that carbohydrates of various types constitute a significant proportion of plum/prune preparations and byproducts.