A study of colour evolution in dry cured sausage manufactured using industrial technology was made. Parameters which define changes related to nitrosation during curing were determined. The main changes in the colour characteristics of Spanish sausage took place during the fermentation stage. pH, nitrate and nitrite concentration, pigment nitrosation index, pigment discoloration index, a^∗, b^∗, C^∗ and H^∗ values decreased during this stage. However, the nitrosation of the myoglobin pigment continued during the whole curing process. The percent conversion of total pigments to the cured nitric oxide heme pigment form was about 70% in the minced mix, and it increased gradually to about 90% in the final product. During fermentation nitrites reacted with myoglobin (Mb) to form nitrosomyoglobin (NOMb) and metmyoglobin (MetMb), which reduced to NOMb during the drying process.