An arrangement for distribution of cooling liquid in the cooling liquid jacket in an internal combustion engine having cylinders disposed in-line in the cylinder block or in a bank of cylinders of the engine. The liquid jacket includes a liquid inlet chamber at one end of the row of cylinders and a liquid outlet chamber at the same end or at the opposite end of the row of cylinders and, in the cylinder block or bank of cylinders with associated cylinder head, mutually interconnected cooling liquid spaces and ducts which communicate with those chambers. In the lower portion of the cooling jacket, a liquid distribution pipe running along the row of cylinders is inserted at one side of the row of cylinders and has at one end a liquid inlet which communicates with the liquid inlet chamber. In the wall of the distribution pipe, liquid outlet holes are provided which are distributed along the distribution pipe and placed and directed in the distribution pipe wall so as to direct cooling water flows towards the cylinder tops and/or the spaces between them. These liquid outlet holes in the wall of the distribution pipe have successively increasing diameters away from the end of the row of cylinders where the liquid outlet chamber is situated. The outlet holes are preferably directed obliquely upwards toward the roof of the cooling jacket.