Background: The prevalence and the number of comorbidities increase with age, variety of physical health conditions common to aging may increase the development of mental health problems in the older adult population. The study aimed to assess the effect of comorbidities on physical function and psychological well-being among the elderly. Design: cross sectional descriptive design was utilized. Setting: This study was conducted at the elderly club of Qena city and the outpatient clinic of Qena general hospital. Sample: The total sample size was 350 elderly who were selected by simple random sample. Tools: Four tools were used, (I): It includes socio-demographic data as, age, sex., etc. (II): Charlson Comorbidity Index. III: The function component of the late life function and disability instrument. (IV): The WHO-5 Well-Being Index. Results: Showed that studied elderly ranged from 60 to more than 70 years, most of the studied elderly were female and married, (35%) received university education. Most of the studied elderly have hypertension (84%) and diabetes (81%), and (61.4%) from the elderly have moderate limitation in functional activities while, (38.3%) have slight limitation and (60.6%) from the elderly have poor psychological well-being. Conclusion: Most of the studied sample had DM & hypertension, more than half of them had three diseases & above, they have moderate limitations in functional activities and poor psychological wellbeing. Recommendation: Improve awareness and psychological wellbeing for the elderly and health caregivers through providing health education programs regarding comorbidities and psychological wellbeing.