Bilateral import unit values are constructed to investigate the extent and speed of exchange rate and production cost pass-through into the unit values of Irish imports (total and sectoral) from the UK using Menon's (1996 ) mark-up model. The approach used to measure exchange rate pass-through is based on cointegration and error-correction modelling and the period of analysis is from 1979 to 1995. Full pass-through from the bilateral Irish pound-Sterling exchange rate and from UK producer costs could not be rejected for total and sectoral import unit values for the sample period 1979q1-1995q4. This implies no role for domestic competing prices in explaining the long-run relationship determining unit values of Irish imports from the UK. The results indicate that for aggregate and sectoral unit values of Irish imports from the UK pass-through is incomplete in the short-run.