The purpose of this study is to find an accurate estimate of the exchange rate-CPI relationship in Iran over the past three decades. The results of the Granger causality test in the frequency domain demonstrate a strong causation from the exchange rate to CPI especially in the long run. The results of the wavelet analysis show that in the currency crisis periods, the exchange rate-CPI correlation rises not only for the long run (low frequencies) but for the short run (high frequencies). According to the results of the state-space model, the exchange rate pass-through jumps in the currency crisis periods, consistent with the results obtained via the wavelet analysis.