Opportunity time cost is usually a significant part of the price variable in travel cost demand model (TCM). Thus, its accurate measurement is important to the estimation of demand and benefits evaluation for nonmarket goods. In this paper we evaluate a technique derived by Ward (1983) to find the value of time implicit in a travel cost model. Monetary costs and time are entered as separated arguments to explain trips per year and, under certain conditions, the ratio of the partial effect of time cost to the partial effect of monetary cost reveals the implicit value of time. The often-used technique of assuming an opportunity time cost on the basis of income is examined using the implicit time cost approach of McConnell and Strand.