Different macroeconomic models have stressed the importance of price-adjustment costs to justify the possibility that changes in nominal variables cause changes in real terms. This paper evaluates these costs from a microeconomic perspective. Using a database of Spanish manufacturing firms, the relationship between the frequency of price adjustment and the price diffusion mechanism is analysed, taking into consideration control variables as the figure and sign of the price variation, the firm’s position in the market, firm’s size, etc. The results show the importance of price-adjustment costs, as well as an asymmetric behaviour for positive and negative price variations.