We present in this thesis comprehensive analysis of the outage probability for multiple-input multiple-output (MIMO) systems over quasi static fading channels with and without receive antenna selection. We consider two channel models in the analysis: independent Rayleigh fading and correlated Rayleigh fading. For the independent fading case, we assume that (1) for a given M receiver antennas, the receiver selects the best L antennas that maximize the capacity; (2) the channel state information (CSI) is perfectly known at the receiver, but not at the transmitter; and (3) the fading coefficients change very slowly such that averaging with respect to these coefficients is not possible. Under these assumptions, we derive two upper bounds on the outage probability with receive antenna selection. The first bound is used to show that the diversity order is maintained with antenna selection. The second bound is used to quantify the degradation in signal-to-noise ratio (SNR) due to antenna selection. Furthermore, we analyze the asymptotic behavior of the outage probability for MIMO systems as the number of transmit antennas tends to infinity. We extend our asymptotic results to the case with receive antenna selection. For all cases, we derive explicit expressions for the threshold for the outage probability. For spatially correlated fading channels, in addition to the assumptions made for the independent fading case, it is assumed that the spatial correlation is present at both ends of the wireless communications link, and the transmit and receive correlation matrices may or may not be full rank.