In this paper, the performance of opportunistic amplify-and-forward multi-hop multi-branch relaying systems operating in the presence of co-channel interferences is investigated. Considering transmissions over independent non-identical Rayleigh fading channels, exact and upper-bound expressions for the end-to-end signal-to-interference-plus-noise ratio (SINR) are obtained. Then, the cumulative distribution function (CDF) and the probability density function (PDF) of the upper bounded SINR are studied. Based on these statistics, the system's outage probability is analyzed in closed form. Moreover, we derive an approximate expression for the PDF of the instantaneous end-to-end SINR. Following that, simple expressions for the approximate error and outage probabilities are presented and discussed. The accuracy of the analysis is validated by comparing the numerical results with Monte Carlo simulations, and insightful discussions are provided.