Temperature-induced phase transitions, electrical conductivity, and some magnetic properties of stoichiometric LaMn1-xRhxO3 (0.1 less than or equal to x less than or equal to 0.5) have been studied. The phase transitions of LaMn0.9Rh0.1O3 were investigated by high-temperature X-ray powder diffractometry and orthorhombic-pseudocubic-rhombohedral transitions were observed. The electrical conductivity measurement shows semiconducting property above room temperature. Breaking of slope in the temperature dependence of the conductivity bring the evidence in support of the phase transition for LaMn0.9Rh0.1O3. At low temperature, the compounds show ferromagnetic behavior but the ferromagnetic intensity increases with the increase of the oxygen nonstoichiometry. (C) 2003 Elsevier Ltd. All rights reserved.