B AC K G R O U N D The aim of this study is to investigate the safety and effectiveness of low tidal volume mechanical ventilation in ac ute re sp ir atory di stress sy d r om e (ARDS) patients during prone positioning. M ET H O D S Thirty pat ients with ARDS were chosen for the study. The pat ients who rec e ived vol ume cont r o lled mechanical ventilation in prone pos it ion all oc ated to two groups as low tidal vol ume (6 ml/kg) adm in i st ered pat ients (gr ou p I, n=15) and conv e nt i onal tidal vol ume (10-12 ml/kg) used pat ients (gr oup II, n=15). The goal of vent il at ion is to prov ide an adeq u ate art er ial oxyg enat ion with the results of a PaO2 v al ue betw een 55-80 mmHg or SpO2 88-95% with a PaC O2 v al ue betw een 38-40 mmHg. H eart rates (HR), systolic and dia st olic art er ial blood press ures (SABP/DABP), central ven ous press ures (CVP), respiratory rates (RR), art er ial oxygen part ial press ure/ fract i onal insp ired oxygen conc e nt r at ion rat ios (PaO2/ F i- O2), pos it ive end-exp iratory press ure (PEEP) levels and plateau press ures (Pplat) were recorded just after pron e p os it i oning, at 1. hour and every 3 hours during a 12- h our study dur at ion in prone pos it ion. Student-t and c h i - s q u are tests, Mann-Whitney rank sum or Krusk a l - Wallis tests and Tukey test were used for stat i st ical analysis. p<0.05 was cons id ered to be stat i st ically significant. R E S U LT S T h ere were no signif icant diff er e nces on hem o d yn am i c par am eters (p>0.05). PaO2/ F iO2 r at io inc r e ased sign if icantly at 1. hour in both groups (p<0.05). The differences betw een the FiO2, PEEP and RR val ues were ins i gn ificant (p>0.05). The plat e au press ures were sign if icantly l ower in low tidal vent il at ion pat ients (p<0.05). CO N C L U S I O N S Low tidal volume ventilation in prone position might be considered as a safe and an effective therapeutic strategy in ARDS patients to improve oxygenation with limited lung injury where prone positioning is also indicated.