Dietary factors may influence colorectal cancer (CRC) survival through effects on inflammation. We examined the association between post-CRC diagnosis inflammatory potential of diet and all-cause and cancer-specific mortality in the Women’s Health Initiative. The study included 463 postmenopausal women who developed CRC during follow-up and completed a food frequency questionnaire (FFQ), on average 1.7 years after diagnosis. Women were followed from CRC diagnosis until death, censoring, or the end of follow-up in October 2014. Energy-adjusted dietary inflammatory index (E-DII)® scores were calculated from the FFQ and dietary supplement inventory. Cox proportional hazards models were fitted to estimate multivariable-adjusted HRs and 95% confidence intervals (CIs) for all-cause, total cancer, and CRC-specific mortality with the most pro-inflammatory E-DII scores (tertile 3) as referent. After a median 11.6 years of follow-up, 162 deaths occurred, including 77 from CRC. Lowest tertile (i.e., most anti-inflammatory) E-DII scores from diet plus supplements were associated with significantly lower all-cause mortality (HRT1vsT3 = 0.49; 95% CI 0.31-0.79) compared to the most pro-inflammatory E-DII tertile. Modest associations with total cancer mortality or CRC-specific mortality were observed, though 95% CIs included 1. Consuming a dietary pattern and supplements with more anti-inflammatory potential after CRC diagnosis may improve overall survival among postmenopausal women.