Existing oncology nutrition services lack capacity to meet the demand for nutrition support in cancer. Online resources offer potential to provide wide-reaching nutrition information at low cost. The aim of this study was to assess the acceptability of an online cancer nutrition resource (www.cancernutrition.ie) amongst cancer patients and caregivers. Further objectives included: (1) To gather information on how www.cancernutrition.ie may be improved; (2) To evaluate differences in acceptability between various endpoints. A mixed methods observational, cross-sectional study with cancer patients and caregivers was conducted. Online focus groups (OFGs) gathered opinions on the website, followed by a post participation questionnaire (PPQ) containing six questions (using Likert Scale Scores (LSS)) on the website's usability and acceptability. Acceptability was assessed against multiple acceptability metrics defined by Nielsen (1994), McCreadie and Tinker (2005), and Harrison et al. (2014). Demographics were assessed for significance against accumulated LSS. Qualitative responses were analysed using an inductive thematic analysis approach (Braun and Clarke, 2019) and coded by two independent researchers, followed by summative/conventional content analysis. Fifteen participants completed the OFGs, the majority of which being cancer patients (n = 11) and/or female (n = 10), and n = 13 completed the PPQ. Statistical analysis suggested that the acceptability of an online cancer nutrition resource was not associated with endpoints: age category, gender, area of living, or days since diagnosis. Thematic analysis generated three themes: Theme 1- The Advantages and Potential of the ICN Website; Theme 2 – Problems Identified within the ICN Website; Theme 3 – Additions Suggested for the ICN Website. The PPQ results matched with subthemes that the websites information was memorable (7.5 ± 2.9 LSS), learnable (7.2 ± 3.2 LSS), recommendable (7.3 ± 3.4 LSS) and that participants would revisit www.cancernutrition.ie (7.6 ± 3.0 LSS). However, despite participants appearing ‘satisfied with content’ (Theme 1; subtheme 1) from the qualitative analysis, quantitative scores indicted differently (6.9 ± 3.0 LSS). Findings suggest that an online cancer nutrition resource is acceptable amongst cancer patients and caregivers, highlighting the potential for a low cost, high impact resource. This research has highlighted necessary alterations needed for www.cancernutrition.ie to achieve all nine criteria of practical acceptability, which have since been incorporated. This updated resource is now being evaluated by an expert multidisciplinary panel and will undergo further refinement and updating based on findings from this evaluation.