Introducción: Las estancias hospitalarias prolongadas (EHP) representan un desafío en la gestión hospitalaria. En Perú, la evidencia sobre los factores asociados a este problema es limitada en servicios de medicina interna de alta complejidad. Existen factores no modificables y modificables (administrativos, organizacionales) que influyen en la duración de hospitalización. Este estudio busca identificar factores modificables relevantes para optimizar la gestión hospitalaria. Objetivos: Identificar factores potencialmente modificables asociados a EHP en un hospital de tercer nivel en Lima, Perú, determinando factores administrativos, organizacionales y dependientes del paciente. Materiales y Métodos: Estudio caso-control anidado en una cohorte, realizado con registros hospitalarios de pacientes internados en Medicina Interna en 2024. Casos definidos como pacientes con estancia superior al percentil 75 histórico (≥21 días) y controles inferiores al percentil 75. Variables: administrativas (demoras en exámenes, medicamentos, transferencias), organizacionales (procedimientos retrasados, decisiones tardías de alta, complicaciones), y clínicas (severidad, comorbilidad). Se calcularon OR crudos y ajustados mediante regresión logística. Resultados: Fueron analizados 212 casos y 359 controles. Los factores modificables destacados (p <0,001) fueron retraso en diagnóstico (OR:10,6), úlceras por presión (OR:5,82), infecciones intrahospitalarias (OR:5,28), demoras en transferencias (OR:3,74), procedimientos médicos-quirúrgicos (OR:3,39), disponibilidad de medicamentos (OR:3,43). exámenes diagnósticos tanto internos (OR 2,34) como externos (OR 2,3). Los no modificables: severidad de enfermedad (OR:2,69) y falta de apoyo familiar (OR:8,6; p=0,059). Conclusiones: La EHP está significativamente influenciada por factores modificables administrativos y organizacionales. Optimizar estos procesos hospitalarios podría reducir carga asistencial y mejorar la eficiencia hospitalaria, recomendándose estrategias específicas para hospitales peruanos de alta complejidad.Introduction: Prolonged hospital stays (PHS) represent a challenge in hospital management. In Peru, evidence regarding factors associated with this issue is limited, especially in internal medicine departments of high-complexity hospitals. Non-modifiable and modifiable factors (administrative, organizational) can influence hospital stay duration. This study aims to identify modifiable factors to optimize hospital management. Objectives: To identify potentially modifiable factors associated with prolonged hospital stays in a tertiary hospital in Lima, Peru, evaluating administrative, organizational, and patient-dependent factors. Materials and Methods: A nested case-control study within a cohort was conducted, using hospital records from patients admitted to the Internal Medicine service during 2024. Cases were patients whose hospital stays exceeded the historical 75th percentile (≥21 days), while controls had stays below this threshold. Variables included administrative factors (delays in diagnostic tests, medications, and transfers), organizational factors (delayed medical-surgical procedures, delayed discharge decisions, hospital-acquired complications), and clinical factors (disease severity, comorbidities). Crude and adjusted odds ratios (OR) were calculated using logistic regression. Results: A total of 212 cases and 359 controls were analyzed. Main modifiable factors associated with PHS (p<0.001) included diagnostic delays (OR:10.6), pressure ulcers (OR:5.82), hospital-acquired infections (OR:5.28), delays in external transfers (OR:3.74), delayed medical-surgical procedures (OR:3.39), delayed medication availability (OR:3.43), and delays in internal (OR:2.34) and external (OR:2.3) diagnostic tests. Non-modifiable factors included disease severity (OR:2.69) and lack of family support (OR:8.6; p 0.059). Conclusions: Prolonged hospital stays are significantly influenced by modifiable administrative and organizational factors. Optimizing these hospital processes could reducehealthcare burdens and enhance hospital efficiency. Specific strategies tailored to high-complexity hospitals in Peru are recommended.