Hydrography and dissolved nutrient salts in the surface and interface waters of Unare Lagoon, located in northeastern coast of Venezuela, during dry, rainy and rainy-dry transition periods were studied. A simple method for collecting the interface material was experimented. Dissolved oxygen concentration varied between 3.9-6.1 μmol/l and the interface exhibited impoverishment, because of benthic demand for oxygen. During dry season, the inorganic nitrogen proportion was superior to 3.4 μmol/l and phosphates concentration was 1.3 μmol/l, while silicates increased during rainy period reaching 9.3 µmol. Phosphates and salinity of surface waters followed a simple dilution law during sea water-fresh water mixture. In general, nutrients were influenced by river waters, internal biological production, interactions with sediments and the sea water infiltrations towards the lagoon.