Atomic force microscopy (AFM) has allowed us to obtain molecular resolved images of Langmuir-Blodgett (LB) monolayers of docosanoic acid (DA) deposited on a glass substrate, monolayers of poly-(beta-benzyl-L-aspartate) (PBA) and poly(L-alanine) (PAL) deposited on a mica substrate, and bilayers of PBA and PAL on graphite. Evidence of sample damage by the AFM tip has been shown. Studies in the periodicity and conformation of the molecules on each type of substrate (hydrophobic or hydrophilic) have thus become possible leading to the measurement of the interchain distance for PBA and PAL.