Hydrogen sulfide (H2S) has been recently found to be an endogenous signaling gasotransmitter. Cardiac hypertrophy often develops in the course of heart failure. It is unknown whether or not endogenous H2S protects cardiac hypertrophy. This study was conducted to examine the effects of H2S on cardiac hypertrophy and fibrosis induced by abdominal aortic coarctation and to explore its mechanisms. Male Sprague-Dawley rats were randomly divided into five groups: normal, sham, abdominal aortic coarctation (AAC), AAC treated with enalapril and AAC treated with H2S. One week after surgery, enalapril and sodium hydrosulfide (NaHS)-treated rats were fed for 28 consecutive days and sacrificed. After that, the left ventricle mass index (LVMI), cardiomyocyte size and areas, collagen volume fraction (CVF) of the rats were measured. In the AAC rats, the LVMI, the cardiomyocyte size and areas, and the CVF were all markedly increased while in the H2S groups they were significantly reduced. H2S decreased the levels of Ang-II in the heart, but not in plasma. In addition, H2S also improved the expression of connexin 43 (Cx43). Our results suggest that H2S can significantly suppress cardiac hypertrophy and fibrosis induced by overloaded pressure, possibly by inhibiting the activity of intracardiac Ang-II and by modifying expression of Cx43.