Current meter and hydrographic data were collected in the Yucatan Channel during a month in the autumn of 1970. Currents 15 m above the bottom are characterized by diurnal modulation and oscillations of 4- to 5-day periods. The observed tidal currents are in phase with their counterpart in the Straits of Florida but of insufficient amplitude for consistency with the amplitude of diurnal tide observed in the Gulf of Mexico. The average current observed over the month was 3.9 cm/s toward SSW. Geostrophic current circulation and dissolved oxygen observations indicate a generally southward flow below about 1000-m depth and at all depths in the eastern side of the channel during the latter part of the observation.