Aim To investigate the role of cardiotrophin-1 (CT-1) in the rat model of pressure overload-induced cardiac hypertrophy and the effect of AG490 on the cardiac hypertrophy and CT-1. Methods The model of pressure overload was established by constriction of abdominal aorta. The left ventricular mass index (LVMI) was observed. The mRNA levels of CT-1 and β-myosin heavy chain (β-MHC) were examined by reverse transcription polymerase chain reaction (RT-PCR) method. The circulating and ventricular angiotensinⅡ (AngⅡ) was measured by radiommunoassay. Results Fourteen days after constriction of abdominal aorta, the LVMI of the hypertrophic group was significantly increased than that of the control group (p<0.01) and it was significantly decreased in AG490 group than in the hypertrophic group, but more than in the control group (p<0.01). The circulating and ventricular AngⅡ of the hypertrophic group was increased compared with the control group, and there was a significant difference between the two groups (p<0.01); the AngⅡlevel of AG490 group was less than that of the hypertrophic group, but still more than the control group (p<0.01). The expression of CT-1 mRNA was similar in the hypertrophic group and the AG490 group (p<0.05), and both groups were more than the control group (p<0.01). The expression of β-MHC mRNA in the hypertrophic group was significantly increased than that in the control group (p<0.01) and decreased in the AG490 group compared with the hypertrophic group (p<0.01), but it was still more than the control group (p<0.01). Conclusions The expression of CT-1 may play an important role in cardiac hypertrophy, AG490 may inhibit the expression of CT-1 and the development of cardiac hypertrophy.