Matricellular proteins, a non-structural extracellular matrix (ECM) component, bind to and modulate various molecules including growth factor, cytokine, protease, other ECM components and cell membrane receptors. While most matricellular proteins are hardly expressed in normal adult tissue, they are re-expressed in heart tissue during cardiac diseases. The present study aimed to clarify the mRNA expression profile of matricellular proteins [secreted protein acidic and rich in cysteine: SPARC, hevin, thrombospondin (TSP)-1, -2 and -4, CCN1 and 5, tenascin (Tn) C and N, periostin and osteopontin (OPN)] in hypertrophied right ventricle (RV) of monocrotaline (MCT)-induced pulmonary hypertensive rats. Male Wistar rats were intraperitoneally treated with MCT or saline. Two or three weeks after MCT treatment, echocardiography was performed, and mRNA expression of matricellular proteins was measured by real-time polymerase chain reaction. MCT (2 weeks) induced pulmonary hypertension, RV dysfunction and hypertrophy, which were all worsened 3 weeks after MCT treatment. Expression of mRNA for SPARC, hevin, TnC, TSP-1, -2 and -4, CCN1 and 5, periostin and OPN but not TnN was significantly upregulated in RV of MCT (2 weeks)-treated rats. Expression of mRNA for TSP-4, CCN1 and 5 and periostin was continuously increased in RV of MCT (3 weeks)-treated rats. The present study for the first time revealed the mRNA expression profile for matricellular proteins in RV of MCT-treated rats for 2 or 3 weeks, which will be helpful to clarify the relationship for matricellular proteins and pathogenesis of MCT-induced RV hypertrophy.