Advanced electronic circuits suffer errors caused by multiple sources. For example, radiation can induce transient errors, and manufacturing variations can cause some devices to sporadically suffer errors. Fault tolerance is therefore an important issue in advanced electronic circuits. Digital filters are commonly used in many applications, and therefore, their protection against errors has been widely studied. However, infinite-impulse-response (IIR) filters have received little attention as most of the existing works focus on finite-impulse-response filters. In this brief, a technique to implement concurrent error detection in IIR filters with programmable coefficients is proposed and evaluated. The protection effectiveness is assessed through fault injection experiments that show that it can efficiently detect errors. The cost is estimated using the synthesis results for a 45-nm library. The results show that the area overhead is much lower than that of a duplicated system that can also detect errors.