Abstract The intensities of several LEED beams from clean Pb(110) and Pb(111) surfaces have been measured in the temperature range from 200 to 590 K and 585 K, respectively. For Pb(111) the intensities show a normal Debye-Waller type decrease with increasing temperature up to 585 K, where LEED spots are still visible. For Pb(110), on the other hand, an additional intensity drop is seen at 490 K and above indicating an order-disorder phase transition. The intensity behavior for (10) and (01) beams of Pb(110) is distinctly different in the sense that disordering along the [11̄0] direction is faster than along . This anisotropy in disorder remains visible up to 590 K. where the (01) beam still has residual intensity whereas the (10) beam is indistinguishable from the background. A quantitative evaluation suggests that the phase boundary in the [11̄0] direction is atomically sharp while that in the  direction is fairly diffuse. The evaluation is carried out in terms of an anisotropic order parameter function.