Hydrographic observations obtained during the period 6-13 August 1989 are used to illustrate characteristics of the dense water of the Mediterranean underflow in the southwestern Black Sea shelf/slope region. The inflowing warmer and saltier Mediterranean water is observed to spread north-northwestward of the channel-canyon axis along the bottom of the shelf. As the inflowing water crosses the shelf it becomes gradually cooler, fresher and thus less dense by mixing continually with the waters of the Cold Intermediate Layer (CIL). Beyond the shelf break, the slightly denser water of the Mediterranean underflow interacts with the thermocline waters of the ambient environment and is finally interleaved in the form of a neutrally buoyant, relatively colder plume in or beneath the halocline. Observations show multiple interleaving layers with thicknesses less than 50 m and temperature differences of about 0.1-degrees-C at depths of 200-300 m. At depths of 400-500 m, intrusions may be distinguished from the ambient environment by temperature differences of the order of 0.01-degrees-C.