KPCC president Ramesh Chennithala said Gandhi will address UDF rallies on April 6 at Harippad, Thrissur and Kozhikode.
Chennithala is the Congress candidate for Harippad in Alappuzha district.
The Prime Minister would address UDF campaign meetings at Kollam and Kottayam on April 9.
Other top Congress leaders slated to visit the state are AICC General Secretary Rahul Gandhi, Union ministers Pranab Mukherjee, Salman Khursheed, Veerappa Moily and Vilasrao Deshmukh.
Defence Minister A K Antony is already in Kerala for a week-long campaigning across the state.
For the LDF, CPI(M) general secretary Prakash Karat is scheduled to arrive in the state today and would address a series of meetings in different parts of the state.
BJP leader Sushma Swaraj is also in the state for canvassing votes for her party.