The invention relates to a tamping unit (1) for tamping sleepers (3) of a track (4), comprising oppositely positioned tamping tools (14, 17) which are connected in each case to a squeezing cylinder (9, 15) for generating a squeezing motion, wherein an eccentric drive (11) is provided for generating a vibratory motion. In this, it is provided that a first squeezing cylinder (9) is connected mechanically to the eccentric drive (11), and that a first pressure chamber (18) of the first squeezing cylinder (9) is connected hydraulically via a connecting line (22, 27) to a second pressure chamber (20) of a second squeezing cylinder (15) in order to transmit a pressure change, generated in the first pressure chamber (18) by means of the eccentric drive (11), to the second pressure chamber (20).