<P><B>Highlights</B></P><P>► Enzymatic hydrolysis may be improved with NaBH<SUB>4</SUB> use in chemical pretreatment step. ► NaBH<SUB>4</SUB> treated straw gave 83.3% glucan conversion in enzymatic hydrolysis. ► Four percent NaBH<SUB>4</SUB> (60min) pretreatment resulted in the highest ethanol yield of 115g/kg. ► Calculated theoretical yield (86.9%) was highest for 4% NaBH<SUB>4</SUB> pretreated sample.</P> <P><B>Abstract</B></P><P>In this study, the aim was to examine bioethanol production of wheat straw residues using an alternative chemical, sodium borohydrate (NaBH<SUB>4</SUB>) in chemical pretreatment step. The obtained results showed that sodium hydroxide (NaOH) and NaBH<SUB>4</SUB> treated straw resulted in 87.8% and 83.3% glucan conversion in enzymatic hydrolysis, but hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) (74.7%) and sulfuric acid (H<SUB>2</SUB>SO<SUB>4</SUB>) (71.7%) had lower glucan conversion. The highest ethanol yield from untreated straw (115g/kg) was observed for 4% NaBH<SUB>4</SUB> pretreated sample (60min) and the theoretical yield (86.9%) was also calculated to be highest for the sample.</P>