Abstract Ba 0.5Sr 0.5TiO 3 (BST) thin films have been fabricated by pulsed laser deposition with the objective of integrating oriented epitaxial ferroelectric films on high- T c superconducting YBa 2Cu 3O 7− x (YBCO) thin films. Perovskite-type BST (100) films grown at 550°C–620°C on c oriented YBCO thin-film substrates exhibited good crystallinity. Highly aligned BST (110) films were grown on YBCO (110) substrates over a much narrower temperature range of 565° to 585° C. The morphology of BST (110) thin films is smoother than of BST (100) films. The BST (100) and BST (110) thin films both showed ferroelectric behavior below 250 K, with a maximum remnant polarization of 1.4 μC/cm 2 for BST (100) on c oriented YBCO, and 0.8 μC/ cm 2 for BST (110) on YBCO (110). The temperature-dependent differences in dielectric properties between BST (100) on c oriented YBCO and BST (110) thin-film systems were investigated.