Launch from the Baikonur Cosmodrome; landing with Soyuz 26 capsule 265 km west of Tselinograd.

The main function of the this mission was to swap Soyuz craft with the orbiting crew, in so doing freeing a docking port for a forthcoming supply tanker. Cosmonauts Vladimir Dzhanibekov and Oleg Makarov returned to earth in the Soyuz 26 spacecraft after spending five days on the station.

Following a one day solo flight Soyuz 27 docked with Salyut 6 on January 11, 1978. It was the first ever guest crew visiting the first resident crew on Salyut 6 space station.

Vladimir Dzhanibekov noticed that as he and Oleg Makarov approached the station in Soyuz 27, they were slightly off-course, but he allowed the automatic system to continue and, with 7 metres (23 ft) to go, it corrected the slight alignment error. To the relief of mission control, Soyuz 27 successfully docked at the forward port. While the docking took place, Georgi Grechko and Yuri Romanenko moved into Soyuz 26 and closed the hatches in case of an accident. It was the first-ever docking of three independently launched spacecraft.

The Soyuz 27 crew then encountered their first problem - a balky hatch that opened suddenly and sent Vladimir Dzhanibekov noticed that as he and Oleg Makarov tumbling backwards. The Salyut crew dove into the Soyuz and hugged their first visitors.

The visiting crew brought supplies such as food, books and letters, equipment and a French biological experiment called "Cytos," and Vladimir Dzhanibekov, an electronics expert, inspected the station's electrical system.

One piece of information that the visiting crew didn't immediately tell the station crew was that Georgi Grechko's father had died ten days earlier. Psychologists had decided such knowledge was not in the best interests of a cosmonaut spending several months in space. Oleg Makarov and Vladimir Dzhanibekov informed commander Yuri Romanenko, however, who assumed the responsibility of telling Georgi Grechko when they landed. Years later, Georgi Grechko said in an interview that he also thought the decision was the right one.

The four cosmonauts conducted many experiments, including Rezonans, which was designed to determine if resonant frequencies might threaten the structural integrity of the three spacecraft combination (Soyuz 26, Salyut 6 and Soyuz 27). Additional work were photography of the Earth surface, solar observation and astronomical experiments.

On January 13, 1978 the crews performed for the first time the now-routine exchange of seat liners and centering weights in their respective Soyuz craft. The liners are custom molded for each space traveler, and are needed for launch and landing, and the weights are needed to ensure a proper center of mass for the returning craft so it does not undershoot or overshoot the landing target.