The economic importance that agriculture has had and has in Robecco is testified by the presence of a secular Agricultural Fair and cattle market, officially established on 11 May 1912, but that had already started some years before.

Traditionally fairs coincided with some religious festivity and so in Robecco they chose the religious festivity of S. Majolo whose cult was linked to a small oratory still existing situated in the square and dating back at least to the eighteenth century. Livestock, poultry, agricultural products and equipment filled the square of the country by creating an opportunity for curiosity but especially of exchange between farmers and traders.

The Fair in recent decades has grown in size: every year on May 1 Robecco streets are filled with thousands of people; it has become a great opportunity for trade and knowledge of the products of the economy of the territory. Despite the industrial and craft products are massively present, its agricultural soul remains in the presence of the animals, in the zootechnical exposure, in the show of agricultural machinery, in the stalls of the farms that present their products San Majolo Fair is also an occasion of promoting the territory at the beginning of the season of the navigation along the Naviglio Grande and the proposal of itineraries along the Naviglio and in the valley.

If the 1st may is the climax, the days before and after are rich of events that animate the town: performances, exhibitions, conventions. In particular the evening of 30 April the relic of S.Majolo is carried through the streets of Robecco thus inaugurating the Fair.