A fundamental mechanism involved in cardiac hypertrophy and subsequent heart failure is sympathetic adrenergic hyperactivity accompanied by activation of the renin-angiotensin system, in which noradrenaline (NA) and angiotensin II (ANGII) are primary effectors mediating hypertrophic, apoptotic and fibrotic events in the heart. As NA and ANGII have been shown to affect intracellular calcium in cardiomyocytes, we hypothesize that the calcium-sensitive calcineurin-Nuclear Factor of Activated T-cells (NFAT) signalling pathway is activated downstream of these factors. More specifically, our aim was to investigate isoform-specific activation of NFATs in ANGII and NA-mediated hypertrophy. The NFAT transcription factors have been shown to be important in the regulation of pathological cardiac hypertrophy, and it is likely that each of the four isoforms, termed c1-c4, play specific roles. We have stimulated neonatal ventriculocytes from C57/B6 mice for 5, 10, 15 or 30 minutes, 24 or 72 hours with 1 mM ANGII or 100 mM NA. Hypertrophy was quantified by leucine-incorporation while NFAT activity was quantified on Western blots using specific antibodies against the phosphorylated, inactive form of the isoforms. Our results show that both ANGII and NA regulate the activity of NFATc1 and NFATc4, that NA activate NFATc2 and that neither of them regulate the activity of NFATc3. As today`s main therapies for heart failure aim at antagonizing the adrenergic and renin-angiotensin systems, understanding their molecular mechanisms of action is of clinical importance. To our knowledge, we are the first to show isoform-specific activation of endogenous NFATs in isolated cardiomyocytes and we here demonstrate that ANGII and NA act partly through activation of specific NFAT isoforms.