For the quality control we firstly used the RClimdex 1.0 (available at http://cccma.seos.uvic.ca/ETCCDMI/software.html), which detect some common errors such as maximum temperature cooler than minimum temperature and outliers. Because we found some errors that this software doesn't detect, we applied another methodology. We calculate for each station and for the maximum and minimum temperature the 24-hr changes and establish a threshold of four times the standard deviation of the month of study. This procedure found out more erroneous data, these errors are mostly detected in maximum temperature (79%). The most common errors were: typing errors and confusion between maximum and minimum temperature. Particularly in one station we found a complete month with erroneous data in both variables, so perhaps they input another variable. Different homogenization procedures were used together with the aim of comparison. The Standard Normal Homogeneity Test (SNHT; Alexandersson, 1987), the Buishand Range Test (Buishand, 1982) and the Homogeneity tests proposed by Vincent et al, (2002) using regression models. For the SNHT and Buishand test, the selected tested variable was annual mean of the diurnal temperature range (mDTR) (J.B.Wijngaard et al.,2003), and in some cases we applied these test to mean annual maximum and minimum temperature series, the other test use as a tested variable the annual mean of maximum and minimum temperature separately. To better analyze inhomogeneities we broke up the total period in two parts when an inhomogeneity is indicated. Is important to mention that for Paysandú, for instance, the documented change of location in 1967, is no detected for anyone of the applied test but the changes detected around 1945-46 and 1955-57 were coincident for different tests indicating a real inhomogeneity. A change around the year 1945 is detected in two stations and it seems to be because of the maximum temperature. When the series will be used for climate analysis the inhomogeneities enhanced by the tests should be taken into consideration for proper results.