The elastic properties of Pd39Ni10Cu10P21 bulk metallic glass (BMG) have been analysed using measurements of sound velocities. Different states of the Pd39Ni10Cu10P21 system (glassy state, supercooled liquid (SCL) and polycrystalline state) were obtained by annealing the samples near the glass transition and crystallization onset temperature. The microacoustical technique has been applied to measure local values of longitudinal and transverse elastic wave velocities and their distribution over a specimen. Finally sound velocities V
L and V
T, density ρ, bulk K and shear G elastic moduli were measured for different states. The values of ρ, V
L and K decrease as temperature increases and the transition from glass to SCL takes place. In the crystalline state ultrasonic measurements were performed by the standard pulse ultrasonic technique with low-frequency flat transducer because of high ultrasonic attenuation in this state. Acoustic images (C-scans) demonstrate coarse-grained microstructure in this state. This is assumed to be characteristic of the microstructure obtained by crystallizing BMG.