There has been extensive research and development activities in the field of nanofibrillated cellulose (NFC) materials during recent years, although microfibrillated cellulose was developed already during the late 1970s at ITT-Rayonier in USA. A major impediment for the large-scale use of NFC has been the high-energy use (excess of 30000 kWh/ton NFC in energy consumption). This problem has now been alleviated by a series of different pre-treatment procedures of the fibres prior to the subsequent mechanical cell wall delamination. The focus in practical papermaking applications of NFC is in the reinforcement of paper/board materials (dry strength wet-end additive) and in barrier coating applications. The driving forces in these applications are resource and energy efficiency in papermaking and the vision of substituting fossil-based films with nanocellulose barriers. Nanocellulose has excellent oil, fat and oxygen barrier properties in the dry state, but the oxygen barrier properties deteriorate at high relative humidities and the approaches to alleviate the moisture sensitivity will be discussed. Today, there are many companies in the process of commercializing NFC and several of them have pilot plants/pre-commercial operations and are planning for up scaling. A pilot plant for the nominal production of 100 kg/day (dry based NFC) was also taken into operation at Innventia AB in 2010. The current contribution will highlight critical issues in the production of NFC and discuss various applications and hurdles to be overcome in order to make NFC production for paper/board based end-use applications viable.