According to the Italian Health Ministry in 2017, more than 850,000 individuals in Italy have requested mental health services for various symptoms associated with psychological distress. Moreover, stress can affect not only individuals, but also their romantic relationships. To date, there is a lack of empirically validated measures that assess individuals’ perceptions of chronic and acute stressors. As such, the goal of the present study was to develop and evaluate the psychometric properties of the Chronic and Acute Stress Index (CASI), a multi-item self-report measure designed to assess perceptions of chronic and acute stressors that originate from individuals and affect their romantic relationships. Utilizing self-report data from 849 individuals from Italy collected before June 2019, the CASI was found to have good reliability and showed appropriate convergent validity with stress and negative affect, and discriminant validity with relationship satisfaction and positive affect. Limitations and future directions as they pertain to research, practice, and consultation are discussed.