When resources are limited, plants must partition their energetic resources among life history traits such as maintenance, growth, and reproduction. Thus reproduction in a given year may result in lowered growth rates or reproductive rates in subsequent years. This is known as the Principle of Allocation or the Cost of Reproduction hypothesis. In this study, flowering, fruiting, and leaf output were evaluated during two consecutive growing seasons in a population of Sanguinaria canadensis in Fairfax, Virginia. The objective of this field study was to determine if the energetic investments by plants that reproduced in two consecutive years (2003 and 2004 growing seasons) were sufficient to reduce reproduction and leaf size as compared to plants that only reproduced in a single year (2004 growing season). The study area is situated on the west campus of George Mason University on a slope of 11.9% and is divided into three 10 m × 100 m rows, with each row separated from the adjacent row by an unsampled 10 m × 100 m row. Row one is at the base of a hill parallel to a stream. Row two is at mid-hill and row three at the top of the hill. Sanguinaria canadensis plants were marked individually and reproductive output (including number of inflorescences, fruits and seeds) were measured in both 2003 and 2004. Leaf surface areas were measured utilizing a grid system and a digital camera processed in a freeware computer program by Scion Corporation. Results supported the Cost of Reproduction hypothesis. Reproduction during two or more consecutive years negatively affected leaf size and reproduction as compared to the effects of reproduction during one year. Specifically, plants that produced flowers in 2003 and 2004 showed a reduction in leaf surface area (P < 0.0001) as compared to plants that produced flowers in 2004 only. Also, plants that produced fruit both in 2003 and 2004 had significantly smaller leaf surface areas (P  =  0.0155) as compared to plants that produced fruit only in 2004. These are consistent with previously published studies on the cost of reproduction in spring ephemerals, although this is the first such study on S. canadensis. A row effect was observed which was potentially caused by pH levels. However, despite the row effect, reproduction and leaf area continued to show significant differences over the two years of the study. Thus we state with confidence that, in this case, when a bloodroot plant produces fruit, there is a cost in future flower, fruit, and seed production, as well as in its future photosynthetic surface area.