The group said 37,781 members of the armed opposition had been killed, including jihadists from the Islamic State of Iraq and the Levant and the Al-Qaeda affiliated Al-Nusra Front.
A total of 58,480 loyalist forces, including more than 35,000 soldiers, were also killed.
Included among those killed on the government side were 364 members of Lebanon's Shiite movement Hezbollah.
Another 2,871 unidentified people were recorded as having died, the group said.
The conflict began with peaceful anti-government demonstrations, inspired by similar movements elsewhere in the region, that were brutally suppressed by the regime.
In response, part of the opposition took up arms and the conflict spiralled into civil war.
On Tuesday itself, more than 50 people were killed in Damascus and Aleppo provinces, the Observatory said.
Thirty-one of the dead fell in Aleppo, mainly as a result of helicopter attacks by the regime, using barrel bombs on rebel areas.
The barrel bombs killed 12 children, six women and three men, said the Observatory, which has previously documented hundreds of casualties in similar air raids targeting the northern province.
Another four children and four adults were killed in a mortar attack by rebels against a regime-held neighbourhood in Aleppo city, said the Observatory.
Meanwhile in Damascus province, 12 people were killed. Among them were six children killed by army tank fire on Jabaadin village.
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A total of 58,480 loyalist forces, including more than 35,000 soldiers, were also killed.
Included among those killed on the government side were 364 members of Lebanon's Shiite movement Hezbollah.
Another 2,871 unidentified people were recorded as having died, the group said.
The conflict began with peaceful anti-government demonstrations, inspired by similar movements elsewhere in the region, that were brutally suppressed by the regime.
In response, part of the opposition took up arms and the conflict spiralled into civil war.
On Tuesday itself, more than 50 people were killed in Damascus and Aleppo provinces, the Observatory said.
Thirty-one of the dead fell in Aleppo, mainly as a result of helicopter attacks by the regime, using barrel bombs on rebel areas.
The barrel bombs killed 12 children, six women and three men, said the Observatory, which has previously documented hundreds of casualties in similar air raids targeting the northern province.
Another four children and four adults were killed in a mortar attack by rebels against a regime-held neighbourhood in Aleppo city, said the Observatory.
Meanwhile in Damascus province, 12 people were killed. Among them were six children killed by army tank fire on Jabaadin village.
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