The micromechanical behavior of single-crystalline Cu6Sn5 is studied by micropillar compression in a picoindenter. The compound Cu6Sn5 is important because it is used as a structural material in microbumps of advanced electronic packages. Micropillars of Cu6Sn5 with known crystallographic orientations were fabricated by focused ion beam machining. Pillars with the c-axis perpendicular to the load direction tended to possess higher strain to failure and lower Young's modulus. Measured Young's modulus from micropillar compression was compared with results from nanoindentation measurements. The modulus values from micropillar compression were consistently smaller than those from nanoindentation measurements.