A process for improved dewatering and retention in the manufacture of paper, where a retention agent containing anionic groups and being based on a polysaccharide or being an acrylamide-based polymer and an alkaline solution of an aluminate are added to the stock containing lignocellulose-containing fibres and optionally fillers. The pH of the stock prior to the addition of the aluminate should be below about 7 to obtain the desired cationic aluminum hydroxide complexes in the stock. The present process is cost effective and insensitive to the content of calcium in the white water.