In this paper we evaluate the Yarkovsky effect on the motion of NEAs under the assumption that this acceleration depends on heliocentric distance as 1/r² and is characterized by the transverse component Α₂ in the orbital coordinate system. For 94 NEAs values of Α₂ have been found with errors less than 1.5 · 10^-14 AU/day². To evaluate the Yarkovsky effect the model of motion should be as complete as possible. In some instances the Yarkovsky effect can be estimated by using only optical observations. Accounting for the Yarkovsky effect permits to include more optical observations in the orbit fitting process. In determining asteroid masses by the dynamical method it seems to be useful to combine it with Α₂ estimates when a small, perturbed asteroid is used as a test particle.