Atmospheric CO₂ is predicted to increase from current levels of 375 ppm to 550 ppm by 2050. Atmospheric ozone (O₃) is also increasing. Increases in these atmospheric gases can have profound impacts on the growth and productivity of crop plants: CO₂ through its direct impacts on photosynthesis and plant water use, and O3 through its direct negative impacts on photosynthesis. Further, tissue chemical composition may be affected through altered rates of resource accrual or allocation. Here we report data on effects of increased levels of CO₂ and O₃ on tissue N & P contents in soybeans from a large-scale, multi-investigator FACE study. We monitored biweekly growth and seed yield for field-grown soybean crops exposed to current and future-predicted atmospheres of CO₂ and/or O₃ for three consecutive years (2004 - 2006) and assessed tissue chemistry on a monthly basis for 2005. We evaluated tissue N & P contents of soybean roots, stems, leaves, pods, seeds and leaf litter for field-grown soybean crops exposed to current and future-predicted atmospheres of CO₂ and/or O₃. Increased CO₂ availability resulted in increased aboveground net productivity and seed yield. In contrast, in 2005, elevated O₃ reduced soybean productivity and seed yield, but elevated CO₂ ameliorated this response. In addition, soybeans grown at elevated O3 levels produced smaller seeds. Overall, these results suggest that soybean crops exposed to high levels of O₃ may experience reduced productivity and yield, but that elevated CO₂ may reduce these negative impacts.