I'm thinking of repainting my concrete basement floor. It was painted with oilbase paint 25 years ago and isn't really peeling off, just needs redone due to wear. After cleaning, can I just repaint without using primer?

Thank You

If the paint is in good condition paint over it with oil-based paint. Remember that a few light coats are better than one thick coat to prevent new paint from peeling. Let each coat dry before applying next coat. Follow the directions on the paint you purchase. Another thing to do is to seal it with an oil-based poly made for floors.
Floor Paint - Oil Based

Thanks.