Volunteering is a popular activity among middle-aged and older adults as means to contribute to the society and to maintain personal health and wellbeing. While the benefits of volunteering have been well-documented in the current literature, it does not tend to distinguish between various types of volunteering activities. This cross-sectional study aims to compare the effects of instrumental (e.g. food preparation, fundraising) and cognitively demanding volunteering activities (e.g. befriending, mentoring) in a sample of 487 middle-aged and older Hong Kong Chinese adults. Participation in instrumental and cognitively demanding volunteering, life satisfaction, depressive symptoms, cognitive functioning and hand-grip strength were measured. The results of two-way between-subject robust analyses of variance demonstrated significant main effects of volunteering type and their interaction effect with age on life satisfaction and depressive symptoms. Comparisons among four volunteering groups (no volunteering, instrumental volunteering, cognitively demanding volunteering and both types) revealed that individuals engaging in instrumental volunteering exhibited lower life satisfaction and more depressive symptoms compared to those who engaged in cognitively demanding volunteering and those who did not volunteer at all. This detrimental pattern of instrumental volunteering was only seen in middle-aged adults, but not in older adults. Findings of this study revealed distinctive effects of two volunteering types, and provide valuable directions for designing future volunteering programmes.