In this study, natural mortality factors of Citrus Leafnniner, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) were investigated under field conditions. The studies were carried out in a lemon orchard in Adana, Turkey during 2007-2008. Ten trees were selected and weekly one shoot from each tree, and a total of ten shoots, were collected randomly during May-November. In the laboratory, the first 15 leaves were checked using a binocular microscope. All biological stages of the pest and the parasitoids, dead or infected individuals, and empty mines, were counted. According to the method and symptoms of predation, the mortality factors of the pest were recorded. In 2007 and 2008, large numbers of larvae were parasitized (46.25% and 48.12%, respectively). The larval parasitoid Citrostichus phyllocnistoides Narayanan (Hymenoptera: Eulophidae) was the abundant species in both years. The third instar of the host had the highest percent of parasitized individuals. In the first year, 15.33% of the pest were consumed by spiders, 10.07% by Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and 3.14% by ants, whereas in the second year these ratios were 16.61%, 8.57% and 3.78%, respectively. Second instar larvae were the most preferred stage for predation. In 2007, in 13.66% of the mines no pests were recorded, whereas the mortality source of 5.19% of the larvae and pupae was not detected. In 2008, these ratios were 10.21% and 6.87%, respectively. It was determined that predators are as effective as the parasitoids in the biological control of the pest.