PURPOSE Digitalization of the health care system is transforming cancer patient care. Although many studies have investigated the determinants of a limited digital health literacy, the association between frailty factors and overall survival (OS) of these patients has never been assessed. METHODS A retrospective noninterventional study included 15,244 adult patients with cancer diagnosed between January 1, 2015, and December 31, 2017, and treated at the Centre Léon Bérard. Limited e-health literacy was defined as the absence of an e-mail address in the electronic patient record. An Inverse Probability of Treatment-Weighted Kaplan-Meier estimate and a multivariate Cox proportional hazards model including interaction terms were used to adjust for confounding on measured covariates. RESULTS In total, 15,244 adults with cancer were included: 55% women, with a median age of 62 years (19-103), and 35.5% had a metastatic disease. More than half (n = 8,771, 57.5%) had entered their e-mail address in their electronic patient record, and 4,020 (26.4%) opened their own patient portal. The median follow-up was 3.6 years (range: 0-6.8). Inverse Probability of Treatment-weighted Kaplan-Meier estimates showed a significantly better OS for patients with an e-mail address ( P < .001). In multivariate analysis integrating interaction terms, male gender (hazard ratio [HR] = 1.27; 95% CI, 1.15 to 1.41; P < .001), older age (HR = 1.02; 95% CI, 1.02 to 1.03; P < .001), de novo metastatic setting (HR = 2.63; 95% CI, 2.47 to 2.79; P < .001), and no e-mail address (HR = 1.63; 95% CI, 1.33 to 2.00; P < .001) were significantly associated with worse OS. CONCLUSION Our results support a strong association between the limited level of literacy and OS. A more in-depth study integrating variables such as socioeconomic level and location of residence would enrich these results.