The study aimed to evaluate the yield and economic effectiveness of spring barley grown in crop rotation and cereal monoculture under three tillage systems. The experimental factors were crop sequence systems: 1) crop rotation (peas – spring barley – winter wheat) and 2) cereal monoculture (spring barley – winter wheat – winter wheat) and tillage systems: a) conventional tillage (CT), b) reduced tillage (RT), and 3) herbicide tillage (HT). Spring barley grain yield was significantly higher in crop rotation than in cereal monoculture. Also, yield was significantly higher under RT than under CT and HT. The number of weeds per m^-2 in cereal monoculture was significantly higher than in crop rotation. Also, more weeds occurred under RT than under CT and HT. Air-dry weight of weeds was higher in cereal monoculture than in crop rotation and it was also higher under RT than under CT. In crop rotation, for each tillage system the production value (EUR ha^-1) was higher than in monoculture, whereas the highest production value (EUR ha^-1) was achieved in crop rotation in RT sites. The economic analysis showed a clear competitive advantage of RT sites with crop rotation over other sites. The proof is the highest gross margin and income from activity, and the lowest unit cost of production.