AP2/EREBP transcription factors (TFs) play functionally important roles in plant growth and development, especially in hormonal regulation and in response to environmental stress. Here we reported verification and correction of annotation through an exhaustive cDNA cloning and sequence analysis performed on 145 of 147 gene family members. A RACE analysis performed on genes with potential in-frame up-stream ATG codon resulted in identification of At2g28520 as an authentic AP2/EREBP member and corrected ORF annotations for three other members. A further phylogenetic analysis of this updated and likely complete family divided it into three major subfamilies. The expression patterns of the AP2/EREBP family members among the 11 organ or tissue types were examined using an oligo microarray and their hormonal and environmental responsiveness were further characterized using cDNA custom macroarrays. These etailed expression profile results provide strong support for a role for AP2/EREBP family members in development and in response to environmental stimuli, and a foundation for future functional analysis of this gene family.