Current studies on bed-blocking or delayed discharge for non-medical reasons report important variations depending on the country or setting under study. Research on this subject is clearly important as the current system reveals major inefficiencies. Although there is some agreement on the patient-related factors that contribute to the phenomenon, such as older age or a lack of functional ability, there is greater variability regarding environmental or organizational factors. This study sought to quantify the number of cases and days inappropriately spent in hospital and identify patient characteristics and healthcare service use associated with the total length of stay. All cases of delayed discharge were studied at the hospitalization units of a general university hospital in Northern Spain between 2007 and 2015. According to regression estimates, the following characteristics were related to a longer stay: higher complexity through (Diagnosis-Related Group) DRG weight, a diagnosis that implied a lack of functional ability, surgical treatment, having to wait for a destination upon final discharge or return home. After an initial increase, a reduction in delayed discharge was observed, which was maintained for the duration of the study period. Multi-component interventions related with discharge planning can favor a reduced inefficiency with fewer unnecessary stays.