OBJECTIVES: This study aimed to investigate the effectiveness of Brief Behavioral Activation Therapy (BBAT) on apathy symptoms in older adults with Alzheimer's disease (AD) in a medical center facility. METHOD: In an experimental design, 90 older adults with AD were replaced into three groups including two experimental groups (mild AD group ( RESULTS: The mixed ANOVA revealed significant differences in all apathy dimensions (executive, emotional and initial symptoms) among the groups. Specifically, significant between-subject and within-subject differences, respectively for group main effect and time main effect, along with a significant interaction between group and time. These findings indicated that apathy symptoms in patients with mild AD significantly decreased from pretest to post- intervention, but there wasn't significant change in moderate AD and control group. CONCLUSION: The findings suggested that BBAT is effective in reducing apathy symptoms in patients with mild AD. Early evaluation, diagnosis and treatment of apathy in the mild stages of AD are crucial for improving patient outcomes.