The behavior of three-dimensional bond fluctuation model chains tethered on an adsorbing flat surface was simulated by the Monte Carlo method. The dependence of the number of surface contacts M on the interaction strength e and the chain length N was investigated by a finite-size scaling law M = N[a0 + a1N1/vk + O((N 1/vk)2)] for e near the critical adsorption point ec

i.e.

k ≡(e-ec)/ec closes to 0. The critical adsorption point was estimated to be ec = 0.93

and the exponents  = 0.49 and 1/v= 0.57.