In the relay systems under interference channels, the overall system performance is more affected by co-channel interference (CCI) rather than by an additive white Gaussian noise (AWGN), due to the aggressive frequency reuse for high spectrum utilization -. Thus, it is required to better understand how the CCI affects the performance of relay systems. Recently, an enormous research has been conducted to analyze the performance of the interference-limited relay systems -. For example, the outage probabilities of amplify-and-forward (AF) and decode-and-forward (DF) relay systems have been derived in closed form when both the desired channel and interference channel undergo a Rayleigh fading , . In  the outage performance has been derived for DF relaying system when the relay node is corrupted by Nakagami-m multiple CCIs and the destination node is suffered by AWGN. Meanwhile, it is known that a Weibull distributed modeling exhibits an good fit to experimental fading channel measurements for both indoor and outdoor environments with a reasonable physical basis given in  (cf.  and references therein). Based on these facts, we analyze the outage performance of the interference-limited AF relaying system, in which both the relay and destination nodes are subject to the arbitrary number of statistically independent and identically Weibull-distributed CCIs. In order to obtain the outage probability, we derive the cumulative density function (CDF) by exploiting the moment based estimators given in , which allows us to provide a simple, yet precise closed-form approximate expression for the outage probability of the AF relaying system.