Unit hydrograph is probably the most used rainfall-runoff model in hydrology. In general it can be said that there are two general unit hydrograph models: the synthetic unit hydrograph model which can be estimated without rainfall-runoff data and the generalized unit hydrograph model which needs rainfall-runoff data. A general review of the proposed estimation procedures of the generalized unit hydrograph model is presented here. About 35 different estimation procedures were reviewed here. All the procedures were used to estimate the unit hydrograph in three watersheds of a Colombian region. Also the direct runoff hydrograph was estimated and a comparative analysis is presented. The results shows that there is a group of excellent estimation procedures and a group that does not gives good results. The obtained results are in agreement with results obtained in other reported researchs in Colombia and in the United States and Europe. Some conclusions and recommendations are also presented.