Differential survivorship within or between stages is an important component of most explanations of turtle reproductive patterns. We tested the null hypothesis that a sample of adult female Trachemys scripta found killed by predators was a random sample of adult females found nesting at a site in W-central Illinois by comparing plastron lengths of the two samples. Mean plastron length of 19 dead female T. scripta was significantly smaller than mean plastron length of 79 females found alive. Apparently smaller females were at greater risk of mortality than were larger ones. Cubic spline analysis indicated that mortality was strongly concentrated among the smallest and perhaps youngest nesting females and was distinctly nonlinear. This finding was consistent with the suggestion that the minimum threshold of maturation size was influenced by the size at which the probability of predation decreases.