This study estimates an aggregate import demand function for Thailand. The earlier studies on import demand based on time series date did not deal with the issue of stable of the time series before estimation. Using the cointegration approach, we find aggregate import demand for Thailand to be price inelastic, cross price inelastic (with respect to domestic price) and income inelastic in the short run. In the long run, aggregate import demand is still price inelastic and cross price inelastic. However, aggregate import demand is highly income elastic in the long run.