Horwath says the NDP would raise the corporate tax rate from 11.5 to 12.5 per cent to pay for major projects like public transit expansion.
The party would also dedicate $29 billion over ten years to fund transit and transportation projects, including a downtown relief subway line for Toronto and year-round daily commuter train service to St. Catharines and Niagara.
Horwath says spending scandals under the Liberal government, like mismanagement at eHealth Ontario and the Ornge air ambulance service, have meant money that could have been used for transit is going elsewhere.
She says an NDP government will "clean up this corruption" and focus on the priorities of Ontarians.
Both the Liberals and the Progressive Conservatives have warned that the NDP promise of a corporate tax hike could put jobs at risk.