The nuclear factor of activated T cells (NFAT) plays a key role in gene transcription in both immune and non‐immune cell types. Genetic ablation of individual NFAT proteins produces complex phenotypes in mice; in particular, NFAT1^–/– and NFAT2^–/– T cells show overproduction and underproduction of IL‐4, respectively. We have taken a positive approach to the question of whether these two NFAT family members differentially regulate IL‐4 gene transcription. Using constitutively‐active NFAT proteins with alanine substitutions instead of phosphorylated serine residues in the regulatory domain, we find that NFAT1 and NFAT2 are both positive regulators of IL‐4 gene transcription, intrinsically very similar in their ability to induce and sustain transcription of the IL‐4 gene. Thus the disparate phenotypes of NFAT1^–/– and NFAT2^–/– T cells do not reflect differences in DNA‐binding or transcriptional activity at the IL‐4 gene, but most likely arise from differential regulation of the two proteins or other indirect effects.