Introduction: Nursing care is among the most important components in provision of quality health care, Missed nursing care (MNC) has been defined as any required patient care omitted (in part or in whole), or delayed. Objective: To determine the magnitude of missed nursing care and its associated factor among nurses who work in Adult care unit of 5selected hospitals of Guragea zone southern Ethiopia. Methods: Facility based cross-sectional study using quantitative method was conducted among 209 Nurse from June 30 to July 15.Study subjects were selected by using simple random sampling. The data was collected using a pretested, self-administered questionnaire. After checking completeness, collected data were entered into Epi-data version 3.1 and exported to SPSS version 23 for further analysis. Bivarate and multivariate Logistic regression analysis performed to identify associated factors with missed nursing care and a p-value of less than 0.05 at 95% of confidence interval were considered as having significant association. Result: A total of 197 nurses were participated in the study with response rate of 94.3%. The prevalence of missed nursing care was 76.1%. Nurses with educational level of diploma [(AOR=3.71, 95% CI: (1.101,13.754)], nurse who were dissatisfied with nursing profession [(AOR=3.016, 95% CI:(1.108,8.213)], nurse who work in medical ward[(AOR=7.860,95% CI: (2.255,27.3), nurse who work in surgical wards [(AOR=5.897(1.726 ,20.140)], and nurse who have no plan to leave their current job [(AOR=0.113, 95% CI: (0.02, 0.62)] were factors associated with missed nursing care. Conclusion and Recommendation: prevalence of missed nursing care in the study was high and educational status, job dissatisfaction, working in medical and surgical ward were factors that increased the missing of nursing care. Therefore, the, hospital manger and policy maker have a responsibility to improve nursing care by motivating their staff to increase the satisfaction through different methods