The invention relates to seal assembly for a rotary piston internal combustion engine comprising a rotating block (11) of a rotational shape with radially situated cylinders (12) with pistons (13) and an outer stationary case (10) with at least one intake port (14) and/or exhaust port (15). The outer surface (16) of the rotating block (11) is a rotational surface with a straight line or curved profile curve, on which transverse and/or side sealing parts, which are placed in the stationary case (10), sit. In circular side grooves (2) there is a side seal consisting of circular side sealing segments (1) that are always placed between neighboring transverse sealing strips (3), which are placed in transverse grooves (4). Those sealing strips (3) go through the side grooves (2) across. In the place, where the side sealing segments (1) and transverse sealing strips (3) meet, there are joints (5) with notches (7) for inserting the side sealing segments (1) and transverse sealing strips (3).