Local Ecological Knowledge (LEK) is culturally guided and empirically based knowledge of the relationships among humans, other living beings, and their environment. Assessing LEK has gained recognition as a means to identify the most appropriate community participants to involve in resource assessment, conservation planning, and joint forestry management. I will describe my research which examines LEK in Tanga, Tanzania, a place where biological and cultural diversity are high and human health and livelihoods are key concerns. I assessed LEK of nine popular medicinal plants among 74 participants and used multivariate analyses to examine trends in knowledge. The findings are contrary to what has been found elsewhere with regard to the usual keepers of LEK. Findings also point to the market as an important locus of knowledge transmission and as an important place to begin to identify conservation priorities.