Molecular arrangements and structural defects in lignoceric and stearic acid monolayers were investigated with transmission electron and atomic force microscopes. Lignoceric acid molecules in the monolayer, prepared by a continuous compression method, were regularly arranged in a hexagonal array with the (10) spacing of 0.43 nm. The hexagonal array with crystallographical distortion of 4.0% was extended over 10 nm (crystallographical continuity), and the locally disordered molecular arrangements in the monolayer were also observed. On the other hand, stearic acid molecules in the monolayer, prepared by a multistep creep method, were regularly arranged in a hexagonal array with the (10) spacing of 0.42 nm. The hexagonal array with the crystallograhical distortion of 2.0% was extended over 20 nm. Distinctly disordered molecular arrangement was not observed in the case of the stearic acid monolayer. The higher crystallographical regularity of the stearic acid monolayer might be attributed to effective sintering at interfaces among crystalline domains during the multistep creep procedure.