The semi-diurnal baroclinic tide in the semi-closed channel which lies between the Greek Mainland and Peloponnesus has been investigated. It appears to be generated in the centre of the channel, where a bottom step topography exists. At a location 8km away from the source, its amplitude reaches 3m during spring tides. Modal decomposition of the baroclinic tide indicated that the first mode accounts for 80% of the energy while almost all of the energy is accounted for by the first three vertical modes. During the observational period several upwellingevents occurred.These eventscaused baroclinictidal energyto disappearthrough the weakening of the stratification within 10—20h. The higher modes dissipated much faster than the first mode which continued to gain energy until the isopycnal tilt reached a maximum. The availableset of data indicatesthat thebaroclinic oscillationsmaynot bean internalKelvin-type wave.