Thousands of candidates were prevented from filing nominations. In many places, the opposition was prevented from conducting election campaign, it said in a statement.
The polling process was vitiated by widespread rigging, preventing people from voting and violence against opposition candidates, their polling agents and supporters, it said.
The Communist Party of India-Marxist said that in the run up to the elections, there were widespread attacks on Left Front and opposition candidates.
"Around 6,000 CPI-M and Left Front candidates were physically prevented from filing their nominations.
"This led to a situation wherein for the Zilla Parishads in Hooghly, out of the total of 50 seats, the Left Front could not file candidates in 10 seats.
"In 6,191 seats in the three-tier panchayats, Trinamool Party candidates were declared elected unopposed."
The CPI-M statement detailed the statements made by Trinamool leaders and West Bengal Chief Minister Mamata Banerjee against the Election Commission and the threats held out against other parties.
"During the polling which began July 11 and concluded July 25, what was witnessed was a state-sponsored rigging of the elections by the Trinamool Congress.
"In all the districts put together, a total of 4,470 booths were completely or partially captured."
It said the violence during the election campaign and during the polling led to the deaths of 24 CPI-M) workers and supporters.