Tidal streams of the Sagittarius dwarf spheroidal galaxy (Sgr) may be showering dark matter onto the solar system and contributing ∼(0.3-23)% of the local density of our Galactic Halo. If the Sagittarius galaxy contains WIMP dark matter, the extra contribution from the stream gives rise to a step-like feature in the energy recoil spectrum in direct dark matter detection. For our best estimate of stream velocity (300 km/sec) and direction (the plane containing the Sgr dwarf and its debris), the count rate is maximum on June 28 and minimum on December 27 (for most recoil energies), and the location of the step oscillates yearly with a phase opposite to that of the count rate. In the CDMS experiment, for 60 GeV WIMPs, the location of the step oscillates between 35 and 42 keV, and for the most favorable stream density, the stream should be detectable at the 11σ level in four years of data with 10 keV energy bins. Planned large detectors like XENON, CryoArray and the directional detector DRIFT may also be able to identify the Sgr stream.Recently, the Sloan Digital Sky Survey (SDSS) and the Two Micron All Sky Survey (2MASS) surveys [1,2] have traced the tidal stream of the Sagittarius dwarf galaxy (Sgr) more than 360 • around the sky. It is believed that this tidal stream is currently moving through the solar neighborhood, and that it contains dark matter in addition to stars. In this paper we investigate the possibility of detecting WIMP dark matter in this stream via direct detection experiments.The Sagittarius galaxy, a dwarf spheroidal galaxy of roughly 10 9 M ⊙ , is a satellite of our own much larger Milky Way Galaxy, located inside the Milky Way, ∼15 kpc behind the Galactic Center and ∼6 kpc below the Galactic Plane [3]. There are two streams of matter that extend outwards from the main body of the Sgr galaxy. These streams, known as the leading and trailing tidal tails, are made of matter tidally pulled away from the Sgr galaxy. The leading tail may be showering matter down upon the solar system [2]. The flow is in the general direction orthogonal to the Galactic plane and has a speed of roughly 300 km/s (see discussion in §2 below). This speed is comparable to that of the relative speed of the Sun and the WIMPs in the general dark halo. Hence one can hope to detect the stream in direct detection experiments.The detectability depends on the density of dark matter in the stream. The mass-to-light ratio M/L in the stream is unknown, but is plausibly at least as large as that in the Sgr main body; in fact, the M/L in the stream may be significantly larger because the dark matter on the outskirts of the main body would be tidally stripped before the (more centrally located) stars. Various determinations of the M/L for the Sgr main body give values in the range 25 to 100 (see the discussion in [2] and references therein). With our assumptions, we find a density of dark matter in the stream in the range 0.3 to 23% of the local dark halo density. If the dwarf does not contain dark matter or the stream does not pass thr...