Community health volunteers (CHVs) are being used within a growing number of healthcare interventions, and they have become a cornerstone for the delivery of mass drug administration within many neglected tropical disease control programs. However, a greater understanding of the methods used to value the unpaid time CHVs contribute to healthcare programs is needed. We outline the two main approaches used to value CHVs' unpaid time (the opportunity cost and the replacement cost approaches). We found that for mass drug administration programs the estimates of the economic costs relating to the CHVs' unpaid time can be significant, with the averages of the different studies varying between US$0.05-0.16 per treatment. We estimated that the time donated by CHVs' to the African Programme for Onchocerciasis Control alone would be valued between US$60-90 million. There is a need for greater transparency and consistency in the methods used to value CHVs' unpaid time.