To date little information has been collected on the pollination ecology of Ailanthus altissima (Mill.) Swingle (tree-of-heaven) in the U.S. This study was established to determine the insect pollinator fauna visiting A. altissima and to study general pollinator behavior as associated with the tree’s reproductive biology. Insects were collected from flowers on male and female trees at optimum intervals. In each instance, samples were obtained three times per tree across each of three study sites. A list of taxa visiting trees within each site and time of day was developed. The nectar composition and amount of total sugars in the flowers of A. altissima and how these are related to tree sex and time of day was determined. Collected nectar was analyzed using HPTLC to determine which sugars were present and their relative concentrations. Anthrone analysis for determining total amounts of sugar was performed. Nectar was found to be sucrose dominant with values ranging from 0.5 – 4.1mg/mL. Similar amounts of glucose and fructose were found, with values from 0.1 – 1.0mg/mL and 0.2 – 1.4mg/mL, respectively. Visitation patterns of insect pollinators were studied using instantaneous counts and analyzed with a regression analysis. Nectar production and removal in trees was studied using caging and compared using a Kolmogorov-Smirnov test. Relative health of trees was ranked and also considered as a factor in all studies.