989 patients were treated on trolleys, chairs or in other inappropriate bed spaces last month at Galway University Hospital putting the hospital third in the list with only University Hospital Limerick and Cork University Hospital having more.
Nationally, over 10,515 patients were treated on trolleys in October.
INMO General Secretary Phil Ní Sheaghdha said the fact that over ten thousand sick people were treated on a trolley this October is a grim indicator for the level of overcrowding we are bound to see over the winter period adding that staffing is an issue across all hospitals.
In a statement released to the media, she said the HSE and Government must protect frontline services by lifting the recruitment embargo immediately and accelerating the hiring process, which has been hindered by the current pay and numbers strategy.
Ms Ní Sheaghdha warned that without the safe staffing level, patients cannot be assured of a safe service.