This paper investigates the performance of N-hop () amplify-and-forward (AF) relaying systems with both relays and the destination subject to independent and not necessarily identically distributed multiple cochannel interferences (CCIs). Based on a new class of upper bound of the equivalent signal-to-interference ratio (SIR) which is the harmonic mean of the minimum of the first hop SIRs and the minimum of the remaining hop SIRs, new approximate closed-form expressions of the outage probability and the ergodic capacity are derived. Furthermore, we derive the asymptotic expression of outage probability which accurately reveals the achievable coding gain and diversity gain. Finally, numerical results validate the correctness of the derived expressions.