Background. Preoperative fasting (POF) is physiologically and precautionary important during anesthesia and surgery. POF from midnight has been practiced despite the recommended shorter practice. Objective. Assessing preoperative fasting among adult patients scheduled for elective surgery at Kenyatta National Hospital (KNH). Methods. A descriptive cross-sectional study involving 65 surgical patients. A questionnaire of mixed questions on demographics, reasons, source of instructions, opinion on instructions, time, premedication practices, outcome, and complains on NPO was used. Analysis was quantitatively done with SPSS v. 22. Ethical approval was obtained from KNH-UoN ERC. Results. Of the respondents 93.8% lacked knowledge on the correct reasons for POF and felt that the instructions were unclear and less important <50%. POF instructions were administered by nurses 80%, anesthetists 15%, and surgeons 5%. Most of respondents (73.8%) fasted > 15 hours. The POF outcomes were rated moderately challenging as follows: prolonged wait for surgery 44.6%, thirst 43.1%, hunger 36.9%, and anxiety 29.2%. Conclusion. Nurses are critical in providing POF instructions and care, and patient knowledge level is a mirror reflection of the quality of interventions. This underscores the need to build capacity for nurses and strengthen the health system to offer individualized preoperative interventions as well as monitoring and clinical auditing of fasting practices.