The Mdm2-SNP309(T/G) polymorphism has been shown to upregulate transcription of Mdm2 and subsequently attenuate the p53 pathway. Its role in regulating the human response to acute illness has not been reported.Patients from the surgical intensive care unit were prospectively enrolled. SNP309 genotype was determined, and a genotype-based comparison of clinical outcomes was performed.Of the 85 enrolled patients, 41 had wild type (T/T) and 44 had mutant (32 T/G and 12 G/G) genotypes. The mutant-genotype group tended to have a longer LOS in both the surgical intensive care unit (P = .40) and the hospital (P = .08), but these trends did not reach significance. No observable genotype-based differences were noted in any other measured parameters.The Mdm2-SNP309(G) allele may be associated with longer LOS. However, it does not appear to influence any other clinical characteristics, nor can it be used to predict clinical outcome.