A source close to the Guinea-Bissau Education Ministry said on Friday that the students' demands had been met.
"They released him last night. Everything is OK now," Ambassador Rogerio Herbert's son said.
Nearly 150 students took over the flat that serves as the Moscow embassy of the impoverished West African country, went on hunger strike and denied food to the ambassador in protest at the government's failure to pay them their stipends for past 13 months.
"They have suspended their protest because they have received guarantees that the arrears on their grants - which represent up to 11 months - will be paid," the education ministry source said, adding that four months' worth of grants would be transferred to the embassy, which would then give the money to the students.