This open cluster was discovered by Charles Messier and cataloged by him on February 19, 1771. However, as he did an error in data reduction, he gave a wrong position in his catalog so that the object was missing until identified it in 1934.

M48 is a quite conspicuous object and should be a naked-eye object under good conditions. The smallest binocular, or telescopes, show a large group of about 50 stars brighter than mag 13, the total number being at least 80. The more concentrated core extends over about 30 arc minutes, while the outskirts reach out to about 54', corresponding to a linear diameter of 23 light years at its distance of 1,500 light years.

The age of M48 was estimated to amount about 300 million years; the hottest star is of spectral type A2 and mag 8.8; its luminosity is about 70 times that of the Sun. M48 moreover contains 3 yellow giants of spectral types G-K.