The aim of this work was to improve sugarcane bagasse thermochemical conversion to pyrolytic sugars production, particularly to levoglucosan. The experiments were carried out evaluating the effect of acid washing with HNO3 (0.1 wt.%) followed by H2SO4 addition (0.1, 0.2 and 0.3 wt.%) at pyrolysis temperatures of 350, 400, 450, 500, 550 and 600 degrees C was studied by Py-GC/MS. The experimental results showed that HNO3 washing, followed by H2SO4 concentration of 0.2 wt.% at 350 degrees C resulted in an increase in levoglucosan yield between 5 and 7 times the yield obtained when the raw bagasse was processed. Thus, these results are very attractive to improve pyrolytic sugars production in sugarcane bagasse by previously acid treatment to pyrolysis technology. (C) 2016 Elsevier Ltd. All rights reserved.