Order, Supreme Court, New York County (Eugene L. Nardelli, J.), entered November 16, 1990, which granted plaintiffs motion to amend the complaint by adding a cause of action alleging the unlicensed practice of engineering, in violation of the Education Law, unanimously affirmed, with costs.
On a motion to amend pleadings (CPLR 3025 [b]), the court should examine, but need not decide, the merits of the proposed new pleading unless it is patently insufficient on its face (cf., Strook & Strook & Lavan v Beltramini, 157 AD2d 590; Goldberg v Linden Towers Coop. No. 5, 147 AD2d 672). Once a prima facie basis for the amendment has been established, that should end the inquiry, even in the face of a rebuttal that might provide the ground for a subsequent motion for summary judgment (Siegel, Practice Commentaries, McKinney’s Cons Laws of NY, Book 7B, CPLR C3025:ll).
Expert testimony brought to light during the deposition confirmed the existence of a prima facie cause of action. Defendants have failed to demonstrate prejudice attributable to any delay in making the motion. Accordingly, granting the *211motion was a proper exercise of the court’s discretion (Murray v City of New York, 43 NY2d 400). Concur—Carro, J. P., Milonas, Asch, Kassal and Rubin, JJ.