Mesoscale circulation patterns in the adjacent basins of the Strait of Gibraltar were investigated by means of altimetry data. In the Gulf of Cádiz, the pattern is relatively stable with two gyres: a cyclonic gyre close to the southern Iberian coast and an anticyclonic one on the western side of the Strait of Gibraltar. Both structures are located in the right place to convey the surface circulation towards the Strait and feed the Atlantic inflow. In the Alboran Sea, our results confirm that the western anticyclonic gyre is the most stable feature observed, while the eastern cyclonic gyre is subject to great variability. The mesoscale structures fluctuate at seasonal and interannual frequencies, but they may also undergo great changes in a very short time scale. A simple correlation analysis suggests that changes in the upstream Gulf of Cádiz basin may be transmitted through the Strait of Gibraltar to the Alboran Sea with a time delay of around one week.