In this work, the impact of the microstructure and the loading conditions on the mechanical behavior of a beta-rich Ti17 titanium alloy is investigated. For this purpose, two different initial microstructures are considered : (i) a two-phase lamellar alpha + beta microstructure and (ii) a single-phase equiaxed beta-treated microstructure. First, compression tests are performed at different strain rates (from 10(-1) to 10 s(-1)) and different temperatures (from 25 to 900 degrees C) for both microstructures. Then, optical microscopy, scanning electron microscopy, EBSD and X-ray diffraction analyses of deformed specimens are carried out. Whatever the loading conditions are, the flow stress of the as-received alpha + beta Ti17 is higher than that of the b-treated Ti17. Also, because of a higher strain-rate sensitivity, the beta-treated Ti17 is less prone to shear banding. At low temperatures (i.e., T <= 450 degrees C), the deformation behavior of both the as-received alpha + beta and the beta-treated Ti17 is controlled by strain hardening. For the b-treated Ti17 alloy, martensitic transformation is systematically detected in this temperature range. The softening behavior of the as-received alpha + beta Ti17 observed at high temperatures is due to the joint effect of dynamic recrystallization, dynamic transformation, adiabatic heating and morphological texture evolution. For the beta-treated Ti17 alloy, when the temperature exceeds 700 degrees C, stress-strain curves display a yield drop phenomenon, which is explained by dynamic recrystallization.