Continuous quality monitoring in sterilisation processes is paramount importance for supplying sterile materials to the patients. The sterilisation monitoring is required because early prediction of steriliser malfunctioning is impossible, and malfunction gets detected only when it runs. Internationally there are three types of sterilisation monitoring system such as physical, chemical and biological monitoring. The physical monitoring system is dependent on time, temperature and pressure. The chemical and biological monitoring systems are also dependent on the same physical parameters but in addition require the presence of condensing steam for sterility assurance. The main aim of this article is to elaborate differences between the ‘conventional biological indicator’ and the ‘rapid biological indicator’ with their benefits and disadvantages for biologically proven sterility assurances. However, it is not possible to determine whether biological material in the indicator is alive or dead, visually. The article explains that the detection of living spores can be technically challenging, and each and every step should be monitored carefully because spores are highly resistant to harsh environmental conditions. The results show that proper incubation time in an appropriate growth medium and optimal temperature is the only way to detect the living microorganisms in a biological indicator for proper sterility assurance.