Despite its widespread usage in economics and social sciences, the term social capital continues to pose measurement challenges to researchers. Volunteerism, due to its role in fostering skills and promoting interpersonal contact, is often perceived as a reliable indicator of social capital formation. The gap in volunteering rates between individuals born in the US and elsewhere, coupled with the rising inflow of immigrants into the US, has lent credence to Robert Putnam’s assertion that heterogeneity impedes the production of social capital within similar and across different groups. Various logit models derived from Independent Sector’s Giving and Volunteering in the United States 2001 survey confirm that there is indeed a gap in volunteerism between immigrants and individuals born in the US, while holding constant a number of relevant demographic (i.e. human capital) indicators and variables measuring attitudes toward others. Surprisingly, simply asking individuals to volunteer can significantly reduce this ‘gap’ in volunteering between US-born and immigrant groups. Additionally, the results show that a number of other indicators, such as religiosity and trust in others can increase an individual’s propensity to volunteer, regardless of the person’s place of birth. Although models incorporating many human capital measures reveal a tendency to support Robert Putnam’s claims regarding the effects of heterogeneity on social capital, the results presented here suggest that both short and long-term policy adjustments may exist to help bridge the gap in volunteering in diverse communities. Asking individuals to volunteer in the short-term, while providing opportunities to improve human capital measures for immigrants in the long-term can enable US policymakers to offset the negative consequences of heterogeneity Robert Putnam foreshadows in his research.