This article deals with the problem of fault detection for discrete-time switched systems with intermittent measurements. The stochastic variable is assumed to be a Bernoulli distributed white sequence appearing in measured output. Attention is focused on designing a fault detection filter such that, for any control input and unknown inputs, the estimation error between the residual and the fault is minimised in the sense of H-infinity-norm. By employing a Lyapunov-like function and average dwell-time technique, a sufficient condition for the existence of such a filter is exploited in terms of certain linear matrix inequality. Finally, an example is provided to illustrate the effectiveness of the proposed approach.