Background: Many genetic variants have been identified as associated with colorectal cancer (CRC) risk; few have been associated with CRC survival. Identification of variants associated with survival may further explain the biology of disease progression and aid in outcome prediction. We performed a genome-wide association study (GWAS) in 2 CC clinical trials to identify genetic variants associated with overall survival (OS). Methods: We included patients from N0147, a phase III adjuvant trial in stage III CC patients, and C-08, a phase III trial comparing adjuvant therapy regimens for patients with stage II/III CC. 4974 samples were genotyped with the Illumina HumanOmniExpress + Exome array, consisting of 964,193 SNPs. Genotypes were imputed using 1000 Genomes Project data. We calculated OS as time from randomization to death from any cause and used Cox proportional hazards regression to evaluate association of each SNP with OS, adjusting for age, sex, treatment arm and principal components. Analysis was performed in N0147 and C-08 separately; results were combined in a fixed-effects meta-analysis. Results: Follow-up after diagnosis was similar for the 2 trials; median OS for N0147 and C-08 was 1678 days (IQR = 1238-2071) and 2224 days (IQR = 1901-2494), respectively. A locus on chromosome 7p15.2 was significantly associated with improved OS. The most significant variant at this locus, rs76766811 (p = 1.59e-8), is exceedingly rare in this primarily European American population but much more common in African Americans (AAs) (~19%). When the analysis is stratified by self-reported ancestry, the signal is only present in AAs (n = 359) (HR = 0.30, 95% CI: 0.21-0.43, p = 1.81e-10). Conclusions: This GWAS nested within 2 CC trials identified rs76766811 on 7p15.2 as significantly associated with OS among AA patients. This finding should be confirmed in additional study populations, particularly focusing on identifying variants associated with survival in AAs. Support: NIH R01 CA176272, U10CA-180868, -180821, -180822, UG1CA-189867, U24CA-196067, PA DoH (which disclaims certain responsibilities), Genentech, Inc., Sanofi-Synthelabo Inc.