A study was conducted to determine the contributions of pathogenic fungi and insects to the mortality of sugar maple (AcersaccharumMarsh.) seedlings during their first season of growth. Replicated plots were located in four northern Pennsylvania stands in which the anthracnose pathogen,Disculacampestris(Pass.) von Arx, and the pear thrips,Taeniothripsinconsequens(Uzel), were associated with sugar maple seedlings. Survival was quantified for new seedlings treated with water (control), the systemic fungicide benomyl, the systemic insecticide acephate, or both, during May through August 1990. Treatment affected mean survival (p < 0.001), which was approximately 2–3 times higher in plots treated with benomyl and acephate than in plots treated with water only. Treatment with the fungicide, insecticide, or both also generally increased the percentage of seedlings bearing leaves (p < 0.001), the number of leaves per seedling bearing leaves (p < 0.001), shoot weight (p = 0.015), and root weight (p = 0.018). Diseases caused by fungi and damage from insects may be the major factors affecting survival of new sugar maple seedlings.