Background Geriatric assessment (GA) has been shown to be pivotal to the prognosis of elderly cancer patients. A G8 screening tool could act as a potential surrogate to identify patients who would benefit from further GA in a busy oncology clinic and a digital version would allow for a wider application. Objectives To develop a digital self-reported version of G8, and to compare its outcomes with in-person G8 administered by a healthcare professional. Methods A total of 483 cancer patients aged 70 years and older who received an in-person G8 assessment at the National Cancer Centre Singapore (NCCS) clinic, and another 544 who completed the digital self-reported G8 were analysed. Total G8 score ≤14 was defined as positive screen. Results Response rate of the digital self-reported G8 was 50%. Median G8 total score was lower among online screeners than in-person screeners (11 vs 12.5, p < 0.001). The odds of a G8 positive screen among online screeners was higher than that of in-person screeners on multivariable logistic regression analysis (odds ratio = 1.56, 95% CI 1.08-2.26). Some 20 in-person screeners had also completed the digital self-reported G8, and the agreement between their in-person and online G8 total scores was high (concordance correlation coefficient = 0.798, 95% CI 0.635-0.962). Conclusions A digital self-reported G8 is feasible. However, given the higher positive screen rate among the online screeners, replacement of the in-person G8 with the digital self-reported G8 should be implemented only after more conclusive evidence on the agreement between in-person and online G8 score is available.