Most residents of long-term care facilities (LTCFs) are patients with chronic diseases requiring long-term care. Unplanned hospitalization of older and frailer residents from LTCFs reduces their mobility and increases the number of infections, complications, and falls that might lead to severe disability or death. This study aimed to identify the critical risk factors associated with unplanned hospitalization among LTCF residents in Taiwan, providing insights that could inform better care practices in similar settings globally. A retrospective study was conducted using inpatient data from a medical center in central Taiwan, covering the period from 2011 to 2019. A total of 1220 LTCF residents were matched with general patients using propensity score matching. Multiple logistic regression analyses were performed to identify factors associated with unplanned hospitalization, controlling for relevant variables. LTCF residents had a significantly higher risk of unplanned hospitalization compared to general patients (OR = 1.44, 95% CI = 1.21-1.73). Key risk factors included advanced age (≥85 years, OR = 1.25, 95% CI = 1.02-1.54), the presence of comorbidities such as diabetes (OR = 1.17, 95% CI = 1.03-1.33) and renal failure (OR = 1.63, 95% CI = 1.42-1.86), high fall risk (OR = 2.67, 95% CI = 2.30-3.10), and being bedridden (OR = 6.55, 95% CI = 5.48-7.85). The presence of a tracheostomy tube also significantly increased hospitalization risk (OR = 1.73, 95% CI = 1.15-2.59). LTCF residents are at a higher risk of unplanned hospitalization, particularly those with specific comorbidities, physical limitations, and indwelling medical devices. These findings underscore the need for targeted interventions to manage these risks, potentially improving care outcomes for LTCF residents globally.