Nosocomial infections remain a major healthcare problem because they increase morbidity, prolong hospitalization, and raise healthcare costs. The prevention of nosocomial infections depends not only on healthcare workers but also on the preventive behavior of patients' family members while accompanying patients during hospitalization. This study aimed to analyze the association between knowledge, attitude, family support, and the availability of health facilities with nosocomial infection prevention behavior among patients' family members in the inpatient wards of "X" Hospital Banjarbaru. This quantitative study employed an analytical observational design with a cross-sectional approach. The study population consisted of 78 patients' family members, and 66 respondents were selected using purposive sampling. Data were collected using questionnaires and observation sheets and analyzed using the Chi-square test at a 95% confidence level. The results showed that 67.7% of respondents demonstrated good nosocomial infection prevention behavior. Most respondents had good knowledge (56.1%), positive attitudes (72.7%), positive family support (66.7%), and were in wards with adequate health facility availability (77.3%).Bivariate analysis revealed significant associations between knowledge (p=0.011; PR=2.734; 95% CI=1.286–5.811), attitude (p=0.040; PR=2.222; 95% CI=1.171–4.218), family support (p<0.001; PR=3.500; 95% CI=1.735–7.061), and the availability of healthcare facilities (p=0.029; PR=2.354; 95% CI=1.260–4.399) with healthcare-associated infection prevention behavior. Strengthening education for family caregivers and ensuring the availability of adequate healthcare facilities are essential to support the implementation of infection prevention behaviors in hospitals.

Keywords: Nosocomial infection prevention behavior, knowledge, attitude, family support, health facility availability.