Variations in thickness and microstructure of ribbons produced by planar flow casting have been investigated as functions of various process parameters. Continuous polycrystalline ribbons of Al-Cu alloy with a thickness range of 50 to 180 ㎛ and a width of 12 ㎜ were fabricated. The ribbon thickness was closely related to wheel velocity, ejection pressure, slot/wheel gap distance, and superheat of molten metal. Microstructural transitions from segregation free zone to cellular/dendritic regions were observed. The thickness ratio of the columnar layer to the entire ribbon thickness and the average inclination angle of the columnar layer increased with increasing the wheel velocity and the superheat of molten metal. X-ray diffraction spectra indicated an increasing tendency towards a ｛200} preferred orientation on the wheel-side surface of the ribbon with increasing the superheat of molten metal. On the air-side surface of the ribbon,｛111｝planes predominated over the entire range of the superheat, and the variation of peak intensity ratios with the superheat was rather negligable.