We report on the writing of lines with resolution of the order of tens of nanometers in Langmuir-Blodgett films using a high resolution scanning transmission electron microscope. The films were layers of manganese stearate deposited by the Langmuir-Blodgett technique onto thin substrates of amorphous carbon. The lines were drawn by an intense electron beam whose diameter was about 1 nm and were observed simultaneously by a low intensity scanning beam. Lines of lighter contrast appeared immediately in the bright field image where the intense electron beam was scanned across the film. It was observed that lines of width 10 nm or less with separations of about 20 nm could be drawn. The charge impinging on the lines was about 5 × 10-3 C cm-2, which is relatively low compared with that used in other methods that produce comparable resolution. Where lines crossed there was very little rounding of the intersections. By a shadowing technique the lines were shown to be deep channels at least 50 nm deep in films which were about 200 nm in thickness. Some possible applications of small structures made in Langmuir-Blodgett films will be mentioned. © 1983.