Surface marine meteorological observations made on board ships that navigate in the Southwestern Atlantic Ocean are regularly collected and verified at the Meteorological Department of the Naval Hydrographic Service of Argentina (DMSHN). The database that contains this information spans from 1950 to present. Due to the importance of these data at the regional scale, a strict quality control (QC) is applied following the recommendations of the World Meteorological Organization (WMO) for marine climatology. The aim of this paper is to describe the development and implementation of an additional QC (statistical). By this technique individual observations that fall out of the statistical limits defined for each selected variable and grid box are trimmed from the database, after which a database suitable for climatological purposes is generated. The sensitivity of the results to the definition of the statistical limits upon different climatic periods, grid spatial resolution and statistical criteria is analyzed. Finally, the resulting seasonal mean values of sea surface temperature and sea level pressure are compared to those obtained with global marine databases.