The Britain-based Syrian Observatory for Human Rights said a total of 271,138 people have lost their lives in the war which broke out on March 2011.
The dead include 79,106 civilians, of whom 13,500 children and 8,760 women.
Non-jihadist rebel fighters killed in the conflict numbered 46,452, while Islamists and extremist fighters -- including foreigners -- numbered 44,254.
The Observatory said the death toll also includes 97,842 pro-regime fighters, over half of them government troops.
On Yesterday, the US and Russia announced a ceasefire deal that would see an end to fighting between forces loyal to President Bashar al-Assad and rebel groups from Saturday.