Minarelli was founded in Bologna in 1951 as a motorcycle manufacturer. In 1956 Minarelli switched to exclusively manufacturing two-stroke engines, in a 2000 square metre purpose-built factory. It employed 20 technical staff and produced 70 engines a day. These were sold to companies in Italy, other parts of Europe and South America.
In 1967 the company changed its name to Motori Minarelli and opened a new plant in Calderara di Reno. By the 1970s engine production had reached 250,000 units a year. Minarelli successfully competed in Grand Prix motorcycle racing with Spanish rider Ángel Nieto winning 125cc world championships in 1979 and 1981.
In 1990 the company began a business relationship with Yamaha. Five years later it employed 350 people and engine production had reached 450,000 units a year. In 2002, following changes in the world motorcycle market, Motori Minarelli became a member of the Yamaha Group.