Presented at the 2013 Aquarius/SAC-D Science Team MeetingIn situ records of sea surface temperature collected between 2005 and 2009 were used to compare, for the first time, the temperature estimated by the Multichannel algorithms (MCSST) of the Advanced Very High Resolution Radiometer (AVHRR) sensors in San Matías Gulf (SMG), in the north of the Argentine Patagonian Continental Shelf (between 40°47'S and 42°13'S). Match-ups between in situ records and satellite sea surface temperature (SST) were analyzed. In situ records came from fixed stations and oceanographic cruises, while satellite data came from different NOAA satellites. The fitting of temperature data to a Standard Major Axis (SMA) type II regression model indicated that a high proportion of the total variance (0.53 ≤ r2 ≤0.99) was explained by the model showing a high correlation between in situ data and satellite estimations. The mean differences between satellite and in situ data for the full data set were 1.64±1.49°C. Looking separately into in situ data from different sources and day and night estimates from different NOAA satellites, the differences varied between 0.30±0.60°C and 2.60±1.50°C. This study may be considered as a basis to make comparisons in future studies involving NIRST temperatures and in situ records in SMG.