AbstractThe carrying capacity of a particular soil depends on the density of the soil that constitutes the layer.  The smaller the value of CBR (California Bearing Ratio) of soil layer of a particular soil type, then the layer made on it should be thicker. In Indonesia, rarely found compacted soil and achieve high CBR value. Soft clay soils that are common in the lowlands or beaches on average have a low CBR value. Soil samples used in this study originated from the  Sukajawa Village, Bumi Ratu Nuban Sub District, Central Lampung. The aim of this research is to know the disturbed CBR value mixed with bagasse ash 6%, and matos weighing 3,5817 gr cured for 28 days then soaked with duration 7, 14, 21, and 28 days. Based on AASHTO classification, this soil belongs to group A-7-6, with LL value 56,69%, PL 26,69%, PI 30,02%. Under condition without immersion, CBR value was 41,8%, and at 7, 14, 21, and 28 day immersion condition, CBR value was 14,6%, 12,8%, 10,7%, and 9,2%. From the results of this study it can be concluded that the soil with a mixture of 6% bagasse ash and matos is good for use as a subgrade in road construction because the CBR value> 6% is soaked for 28 days.Keywords : Soft Clay Soil, Bagasse Ash, Matos, CBR.