This work deals with acid hydrolysis of bagasse in just one step and in a modified step using concentrated sulphuric acid. The study analysed the influence of three independent variables on the single-step process (reaction time, solid percentage of bagasse and temperature). The highest conversion obtained in single-step hydrolysis was 87.65% fermentative sugars, using 70% sulphuric acid with 2% solids at 50ºC for 1 hour. The modified process was carried out based on these results; 97.5% maximum conversion of fermentative sugars was achieved using 30% acid dilution. Concentrated sulphuric acid single-stage hydrolysis of bagasse and in a single modified stage were subjected to technical-economic analysis. Starting from the results obtained experimentally of the process at laboratory level and elevated to a possible plant with a capacity to produce 800 HL alcohol/day. VAN and PRD indices indicated that single-stage concentrated acid hydrolysis Variant 1) having 8,310,659.27 VAN and 3 year PRD was more feasible than the modified process (variant 2) having 3,293,318.69 VAN and 7 year PRD.