The focus of this study was to investigate the determinats of additional voluntary contributions to pension funds in Kenya with Specific aim of finding out the effect of member’s income to additional voluntary contributions. The population for this study consisted of 859 members of four Universities pension funds in South Eastern Kenya. Questionnaire was used to collect primary data which was analyzed using descriptive statistics. The study found out that Member income affected participation on additional voluntary contributions to pension schemes. The study recommends that the Government should proved incentives in form of tax exemptions on income earned by additional voluntary contributions to pension funds and increase exemption rate of pension contributions from the current maximum of Ksh 20,000 per month to encourage members of the pension schemes to make additional voluntary contributions.