Effects of a uniaxial compression on the phase-separation process of a binary mixture of poly(styrene-ran-butadiene) (SBR) and polybutadiene (PB) were studied by means of time-resolved light scattering. For this purpose, the uniaxial compression of gamma(p) = 1 to 0.25 was imposed on the film which was first subjected to isothermal phase separation in the absence of external deformations. The scattering intensity distributions were detected as a function of scattering vector q in the plane perpendicular to the compression axis with the incident beam parallel to the compression axis. After the compression, the scattering vector at a maximum intensity q(m)(gamma(p)) abruptly decreased with gamma(p) nearly in accord with affine deformation. In an earlier time after the compression, the peak scattering vector q(m)(t;gamma(p)) remained unchanged with time t for a certain time period and then decreased in the same manner as that found for the phase separation in the undeformed sample, indicating that a memory effect of the uniaxial compression decays with time. Cahn’s linear analysis after the uniaxial compression in the time range where q(m)(t;gamma(p)) was constant indicated that the growth rate R(q,gamma(p)) of the concentration fluctuations with wave number q depends strongly on gamma(p), clearly revealing that the growth process is nonlinear, depending on the initial state. The effect of the uniaxial compression on the late stage spinodal decomposition was also analyzed : the scaled structure factors perpendicular to the compression axis were determined as a function of gamma(p). The results indicated that the global scaled structure factor was almost identical to that found for the undeformed case, although the local structure was affected by the uniaxial compression.