White button mushroom (Agaricus bisporus) is the most commonly cultivated mushroom species which comprises about 32% of world mushroom production. It is a good source of proteins, amino acids, carbohydrates, vitamins (mainly vitamin D and vitamin B-complex) and minerals, such as iron, calcium, phosphorous and potassium. Agaricus bisporus mushroom is valued for its white appearance and browning of its cap is an indicator of poor quality. Browning and bruising of the mushroom surface lead to reduced shelf-life and lower financial returns to producers, therefore there is a need for objective evaluation of mushroom quality to ensure that only high quality produce reaches the market. Traditional methods have been widely used to evaluate mushroom quality and shelf life based on several quality parameters such as visual appearance, size, colour, maturity stage, development stage, microbial growth and weight loss. However, today’s mushroom industry demands non-destructive, rapid and accurate on-line sensor technologies to monitor and control mushroom quality and safety. In this chapter, some traditional quality grading methods as well as application of novel techniques for mushroom quality and shelf life evaluation are discussed.