Tablets manufacturing in a full production scale is commonly associated with an increase of temperature. Such phenomenon, known since the 60', is mainly due to the length of the process and the high number of tablets produced for each revolution steps. The aim of this work is to study the relationship between working temperature and tablets properties (i.e. hardness and drug release). Acetylsalicylic acid (ASA) controlled release tablets were prepared using polyethylene oxide (PEO) of different molecular weights. Tablets were manufactured in a modified rotary tablets machine able to control ambient conditions (i.e. temperature and humidity), working at 25 or 50 °C with a fixed humidity value of 50%. ASA:PEOs (1:1) physical blends were characterized in term of thermal properties, tableting mechanism (i.e. Heckel and energy analysis), tablets strength and dissolution behaviour. Mechanical and compression tablets properties were influenced mainly by the manufacturing temperature while the molecular weight had a weak effect. On the contrary, the dissolution studies clearly demonstrated a direct influence of PEOs molecular weight, while the temperature of manufacturing process did not showed any significant effect.