Reflectarrays have attracted substantial interest in recent years as low-profile replacements for reflector antennas, particularly in space applications. Tunability adds a new dimension to reflectarrays, enabling them to form dynamically-controllable radiation patterns for beam-forming applications. While various approaches for tuning reflectarray elements have been proposed, successfully demonstrated approaches based on varactor tuning diodes still suffer from loss and linearity issues. Reflectarray elements based on micro-electro-mechanical systems (MEMS) components possess significant potential in addressing these shortcomings. This paper presents the design of an electronically tunable reflectarray element based on MEMS capacitors. The design and measurements of an experimental MEMS reflectarray element are discussed in detail.