Background: Brain stroke causes physical and mental disabilities, as well as dependence on one's family. In such cases, the families suffer from severe crisis and anxiety due to the unexpected incidence of the disease and unawareness of the associated consequences.; Objectives: The aim of the present study was to evaluate the effectiveness of informational support on the level of anxiety in family caregivers of hemiplegic stroke patients.; Methods: This quasi-experimental study was performed on 78 family caregivers of hemiplegic stroke patients admitted to the Neurology Department of Farshchian Hospital in Hamadan, Iran, over 8 months. The subjects were selected through convenience sampling method and divided into two groups of intervention (n = 40) and control (n = 38). Intervention started from the third day of hospitalization and continued until the eleventh day. During this period, information about the ward, equipment, patient status, and care procedure at home, was provided for the intervention group individually and in groups. On the other hand, the control group only received the routine care. Anxiety level of caregivers was measured through the Spielberger scale both before and after the intervention. Data analysis was performed in SPSS software (version 16).; Results: Based on the results, both groups were similar in terms of demographic variables (P > 0.05). Moreover, there was no significant difference between the two groups regarding the mean level of state and trait anxiety before the intervention (P > 0.05). However, after intervention, the mean level of state and trait anxiety of the intervention group showed a significant reduction in comparison to that of the control group (P < 0.05).; Conclusions: According to the findings, it can be concluded that informational support is effective in reducing the state and trait anxiety in family caregivers of stroke patients. Therefore, it is suggested that nurses consider informational support as an important nursing intervention during hospitalization.