This descriptive study investigates the diffusion of electronic portfolios in preservice teacher education by documenting the context and emergent practices in six programs identified as mature in their implementation. Context variables examined include prior use of paper portfolios, pressures for standards-based assessment, and leadership and governance issues. Variations in program implementation are also explored including the portfolio tools employed, artifact selection, evaluation of student work, and the role of reflection. Findings of the study suggest that amidst the common themes across programs, there are numerous variations in approaches to e-portfolio use. The authors conclude that further research is needed to examine the future directions for e-portfolios envisioned as well as specific advice for those in earlier stages of adoption or implementation.