We present CCD photometry in the Johnson U, B and V and Kron-Cousins I passbands for the open cluster NGC 2587. The sample consists of 4406 stars reaching down to V~21.0. We developed a new method to clean statistically the colour-magnitude diagrams. NGC 2587 appears to be a sparse, relatively bright open cluster, with a few tens of members projected on to a populous star field.