Objectives: The aim of this study was to identify new predictors of kidney graft primary dysfunction from results of metabolic, electrolyte composition, and preservation solution effluent osmolality analyses of kidneys from deceased donors. Materials and Methods: Samples of left renal veins in Custodiol preservation solution (produced by Dr. F. Köhler, Chemie, Bensheim, Germany) from kidney explants and from back table surgical procedures were obtained from 55 deceased donors. We compared metabolic parameters (glucose and lactate levels), electrolyte composition (potassium, sodium, calcium, chlorine), and effluent osmolality of kidney samples from donors whose recipients had satisfactory initial graft function (n = 44) and dysfunction (n = 22). Values are shown as median and interquartile ranges between the 25th and 75th percentiles. We used the Mann-Whitney U test to compare quantitative variables. Results: Statistically significant differences were observed in effluent osmolality results between kidneys that resulted in satisfactory graft function (median, 85; interquartile range, 65.5-97.1) and those that did not result in satisfactory graft function (median, 103.25; interquartile range, 78.7-125.75) (P = .045). We also observed a trend toward significance in sodium ion levels (P = .073) and lactate levels (P = .09). No statistically significant differences were shown in samples obtained from the back table surgical procedure. Conclusions: As a predictor of an initially satisfactory functioning deceased-donor kidney graft, it is possible to use the level of osmolality in Custodiol solution effluent obtained at explant.