Objectives: This study aimed to identify factors affecting the length of intensive care unit (ICU) and characteristics among older patients transferred from long-term care hospital. Methods: This is a retrospective study and we extracted data from electronic medical records. Study participants were patients aged 65 or older who were admitted to ICU after they had been transferred to emergency department from long-term care hospitals. Length of stay (LOS) in ICU was defined as the patients had stayed in ICU for 7 days or more. Factors influencing the LOS were identified through the binary logistic regression analyses based on demographic and clinical characteristics and laboratory parameters. Results: Of all screened patients, 243 subjects were transferred from long term care hospitals. Participants mean age was 80.3 (±7.0) years and female comprised 63%. Participants had stayed in ICU for 13.4 days in average. Factors affecting the LOS in ICU were presence of multidrug resistant organism after ICU admission (odds ratio, OR 5.66, 95% confidence interval, 95% CI=1.79-17.82, p<0.010), tracheostomy insertion (OR 3.35, 95% CI=1.28-8.74, p<0.014), mechanical ventilator application (OR 2.49, 95% CI=1.11-5.58, p<0.026), central venous catheterization (OR 2.13, 95% CI=1.09-4.17, p<0.027) and simplified acute physiology score III (OR 0.95, 95% CI=0.91-1.00, p<0.039) by multivariate binary logistic regression analysis. Conclusions: Older patients in long-term care hospitals stayed longer in ICU and were vulnerable to infection. It is important to develop strategies to reduce LOS in ICU as the number of older patients admitted from long-term care institutions increases.