Earlier Prime Minister Narendra Modi tweeted his birthday wishes to Sangma.
Sangma became Chief Minister on his birthday in 2010 after taking over from D D Lapang and regained his position as the leader of the House in the 2013 Assembly polls.
While Lapang failed to handle 'infighting' within the party, Sangma managed to control the internal bickering and that allowed his government to function smoothly.
Opposition parties, however, said Sangma had more failures than success stories during his five years' reign.
Law and order, corruption and crimes against women have risen in these five years and there was no sign of positive development, they alleged.
Opposition chief whip and National People's Party legislator James K Sangma said militant outfits mushroomed under Sangma's rule.
"There were only two militant outfits - the HNLC in the Khasi Hills region and ANVC in the Garo Hills region - in 2010. Today, there are over 21 outfits. This speaks of the law and order situation especially in the Garo Hills," James said.
This is an indication that no real development had taken place during these five years, he said.
"The crime graphs have only risen. A woman was shot dead in South Garo Hills last year, families were executed for allegedly practicing witchcraft earlier this year and even the peace pacts with militant groups were mere lip services," the legislator said.
The NPP leader alleged that corruption is another factor that Sangma failed to check.
As the Chief Minister is busy in domestic and foreign tours, he had little time to address the needs of the people in the state, he said, adding, the tours are also draining the state exchequer.
United Democratic Party working president and former Deputy Chief Minister Bindo Lanong said people of Meghalaya got no result of the Chief Minister's visit to Philippines, Germany and other places.
"Where is the promised rice cultivation after the Manila visit or an improvement in piggery and bamboo cultivation?" he asked.
Charging Mukul Sangma with the deaths of three persons over the National Green Tribunal's ban on coal mining, Lanong said the government had mishandled the situation and that resulted in the deaths.
The Mookhep firing incident which claimed two lives should have been avoided. A police officer was also killed in Ri Bhoi during the NGT ban, he said.
Power shortage, lack of employment opportunities and lackadaisical health-care system are other concerns, the UDP leader said.