The aim of this study was to evaluate the care burden, psychological distress, and psychiatric disorders of the companions of adult patients in the hospital. This study is a cross-sectional descriptive study. The study questionnaire included a sociodemographic information form, the Zarit Caregiver Burden Scale (ZCBS), and the Brief Symptom Inventory (BSI) were administered to the companions. Simple descriptive and inferential statistics were performed. The Mann-Whitney U test was used when there was no normal distribution. Correlation coefficients and statistical significance were calculated by using the Spearman test for at least one non-normal distributed relationship. A multiple linear regression analysis was performed for determining factors associated with BSI scores. The type 1 error level was used as 5% for statistical significance. All p-values of less than .05 were considered significant. Three hundred companions were included in the study. An emotional commitment was the leading cause of companionship. The mean values of the companions’ ZCBS and BSI scores were 20.2 and 34.4, respectively. There was a moderately positive correlation (r = .50) between the ZCBS and BSI scores, and it was found to be statistically significant. ZCBS scores were positively associated with BSI scores. Psychological distress increases as the care burden of companions increases. Companions need more assistance from health care institutions, family members, and the community. The support of health workers and family members reduced the companions’ care burden and psychological distress. Physicians working in the hospital should take into account that companions may be hidden patients.