The Communist Party is the only one allowed in Cuba, though membership is not a requirement to hold political office. The government does not recognize any legal status of opposition groups, which it accuses of being financed from overseas and trying to undermine the revolution.
It was the first pastoral letter from the Bishops' Conference since 1993's "Love Awaits All," which stirred controversy at the time for its criticism of the government.
The new document also applauded President Raul Castro's reform program begun in 2010, which has included things such as increasing private small business activity, legalizing home and used car sales, decentralizing state businesses and ending a widely detested exit visa requirement that for decades made travel abroad difficult for many.
But the bishops said much remains to be done.
They highlighted as an example the low salaries of professional and government workers in key sectors such as health and education, something that Castro recently acknowledged is a problem that must be solved.
The Church also called for dialogue between Cubans of differing opinions, and for Washington to end its 51-year-old economic and financial embargo on Cuba.
"The geographic proximity and family ties between the two peoples are unavoidable realities that should be taken into account in order to encourage an inclusive policy, through respect for differences," it said.
Cuba has a relatively low percentage of practicing Catholics compared with elsewhere in Latin America less than 10 percent, next to 84 percent in Mexico. But the church has played an important role in recent years as one of the few independent institutional voices on the island and an interlocutor with Castro's government.
It was instrumental in negotiating a pact under which the last of 75 opposition activists jailed in a 2003 crackdown were freed from prison in 2010 and 2011.
Last year, then-Pope Benedict XVI made a high-profile trip to the island and met with both Raul and Fidel Castro.
He was following in the footsteps of his predecessor, John Paul II, who visited in 1998 and famously urged Cuba to open itself to the world, and the world to open itself to Cuba.
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Andrea Rodriguez on Twitter: www.twitter.com/ARodriguezAP