We report on CCD optical ( B and V passbands ) and near IR ( J and K bands ) observations in the region of the old open cluster NGC 2141 .
By combining the two sets of photometry ( 500 stars in common ) we derive new estimates of the cluster fundamental parameters .
We confirm that the cluster is 2.5 Gyrs old , but , with respect to previous investigations , we obtain a slightly larger reddening ( E ( B-V ) = 0.40 ) , and a slightly shorter distance ( 3.8 kpc ) from the Sun .
Finally we present Luminosity Function ( LF ) in the V band , which is another age indicator .
We provide a good fit for the age range inferred from isochrones by assuming the Kroupa et al .
( 1993 ) IMF up to M _ { V } = 5.0 .
We interpret the disagreemt at fainter magnitudes as an evidence of mass segregation .